Methods, devices, equipment and storage media for monitoring leaks in fuel evaporation systems

Abstract

This disclosure provides a method, apparatus, device, and storage medium for monitoring leaks in a fuel evaporation system. The method includes: when set monitoring conditions and vehicle status conditions are met, determining that the charcoal canister vent valve and charcoal canister solenoid valve are in normal working condition, and confirming that the fuel tank has passed the first shaking test; then, based on the process of establishing a vacuum in the fuel tank, determining that the fuel tank vent shut-off valve is free from liquid seal issues and first-type leaks; furthermore, based on the rate and amount of fuel tank pressure change during the set process, determining that there are no charcoal canister solenoid valve malfunctions and second-type leaks in the fuel evaporation system. This disclosure solves the problem of insufficient accuracy in leak monitoring under non-stable driving conditions in existing technologies, maximizing the reliability and accuracy of leak monitoring results.

Description

Technical Field

[0001] This disclosure relates to the field of vehicle technology, and in particular to a method, apparatus, equipment and storage medium for monitoring leaks in a fuel evaporation system. Background Technology

[0002] Vehicles equipped with gasoline engines have fuel tanks filled with a large amount of oil vapor due to the volatility of gasoline. During engine operation, this oil vapor is typically introduced into the engine intake manifold through a fuel evaporation system consisting of the fuel tank, charcoal canister, charcoal canister vent valve (or equivalent device, such as an air pump), charcoal canister solenoid valve, and several pipelines. It then enters the engine cylinders with the intake airflow for combustion, improving fuel economy and preventing large amounts of oil vapor from leaking into the atmosphere and polluting the environment. To prevent oil vapor leakage, real-time monitoring of the fuel evaporation system is necessary for timely maintenance.

[0003] The most commonly used method for detecting oil vapor leaks is the engine intake manifold vacuum method. This method requires evacuating air through the engine intake manifold during engine operation to reduce the oil tank pressure to a negative pressure, and then identifying the leak based on the pressure change.

[0004] However, during vehicle operation, unstable driving conditions such as going up and down slopes, acceleration and deceleration, turning, and driving on bumpy roads are common. These conditions can cause the fuel vapor space in the fuel tank to shrink and the fuel pressure to fluctuate, resulting in a decrease in the accuracy of monitoring results. Summary of the Invention

[0005] This disclosure provides a method, apparatus, device, and storage medium for monitoring leaks in a fuel evaporation system, to address the problem of insufficient accuracy in leak monitoring of vehicles under non-stable driving conditions in the prior art.

[0006] Firstly, this disclosure provides a method for detecting leaks in a fuel evaporation system, the method comprising:

[0007] In response to the fulfillment of the set monitoring conditions and vehicle status conditions, it is determined that the charcoal canister ventilation valve and charcoal canister solenoid valve are in normal working condition, and the fuel tank passes the first shaking degree detection.

[0008] Based on the process of establishing a vacuum in the oil tank, it is determined that there is no liquid seal or first-type leakage situation in the oil tank vent shut-off valve. The first-type leakage situation is used to indicate the leakage situation corresponding to the leakage point with an equivalent diameter in the first numerical range.

[0009] Based on the rate and amount of change in tank pressure during the setting process, it is determined that there is no charcoal canister solenoid valve malfunction or second-type leakage in the fuel evaporation system. The second-type leakage is used to represent the leakage situation corresponding to the leakage point with an equivalent diameter in the second numerical range.

[0010] Secondly, this disclosure provides a fuel evaporation system leakage monitoring device, which includes:

[0011] The condition judgment module is used to determine that the charcoal canister ventilation valve and charcoal canister solenoid valve are in normal working condition in response to the satisfaction of the set monitoring conditions and vehicle status conditions, and to determine that the fuel tank has passed the first shaking degree detection.

[0012] The first monitoring module is used to determine whether there is a liquid seal or a first-type leakage situation in the oil tank vent shut-off valve based on the process of establishing a vacuum in the oil tank. The first-type leakage situation is used to indicate the leakage situation corresponding to the leakage point with an equivalent diameter in the first numerical range.

[0013] The second monitoring module is used to determine, based on the rate and amount of change of fuel tank pressure during the set process, whether there is a charcoal canister solenoid valve malfunction or a second type of leakage in the fuel evaporation system. The second type of leakage is used to indicate the leakage situation corresponding to the leakage point with an equivalent diameter in the second numerical range.

[0014] Thirdly, this disclosure also provides a control device, which includes:

[0015] At least one processor;

[0016] and memory that is communicatively connected to at least one processor;

[0017] The memory stores instructions that can be executed by at least one processor to cause the control device to perform a fuel evaporation system leak monitoring method as described in any embodiment of the first aspect of this disclosure.

[0018] Fourthly, this disclosure also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement a fuel evaporation system leakage monitoring method as described in any of the first aspects of this disclosure.

[0019] The fuel evaporation system leakage monitoring method, apparatus, equipment, and storage medium disclosed herein determine that the charcoal canister vent valve and charcoal canister solenoid valve are in normal working condition when set monitoring conditions and vehicle status conditions are met, and confirm that the fuel tank has passed the first shaking test. Then, based on the process of establishing a vacuum in the fuel tank, it is determined that the fuel tank vent shut-off valve is free from liquid seal and first-type leakage. Based on the fuel tank pressure change rate and amount during the set process, it is determined that the fuel evaporation system is free from charcoal canister solenoid valve malfunction and second-type leakage. Therefore, the impact of unstable driving conditions on the accuracy of monitoring results can be effectively avoided. Furthermore, by monitoring different types of leaks and malfunctions in the fuel evaporation system through multiple steps, the reliability and accuracy of leakage monitoring results are maximized. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0021] Figure 1 This is an application scenario diagram of the fuel evaporation system leakage monitoring method provided in the embodiments of this disclosure;

[0022] Figure 2 A flowchart illustrating a method for monitoring fuel evaporation system leaks according to an embodiment of this disclosure;

[0023] Figure 3a A flowchart of a fuel evaporation system leakage monitoring method provided in yet another embodiment of this disclosure;

[0024] Figure 3b for Figure 3a The flowchart for identifying the degree of tank swaying provided in the illustrated embodiment;

[0025] Figure 3c for Figure 3a The flowchart for determining the liquid seal status of the oil tank vent shut-off valve is provided in the embodiment shown.

[0026] Figure 3d for Figure 3a The flowchart shown in the embodiment is for determining whether there is a charcoal canister solenoid valve malfunction in the fuel evaporation system under the first set operating condition.

[0027] Figure 3e for Figure 3a A schematic diagram of the method for determining the rate of increase of tank pressure based on the EWMA algorithm provided in the embodiment shown;

[0028] Figure 3f for Figure 3a The flowchart shown in the embodiment illustrates the process of replenishing air and troubleshooting the solenoid valve malfunction of the charcoal canister.

[0029] Figure 3g for Figure 3a A schematic diagram showing the correspondence between each step of the leakage monitoring and the tank pressure in the illustrated embodiment;

[0030] Figure 4 A schematic diagram of the structure of a fuel evaporation system leakage monitoring device provided in yet another embodiment of this disclosure;

[0031] Figure 5 This is a schematic diagram of the structure of a control device provided in yet another embodiment of this disclosure.

[0032] The accompanying drawings have illustrated specific embodiments of this disclosure, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concepts of this disclosure to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0033] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0034] The following is a description of the terminology used in this disclosure:

[0035] Fuel vaporization system: This system comprises the equipment and components through which gasoline vapors reside and pass from the fuel tank to the engine intake manifold. It includes, in sequence, the fuel tank (or fuel tank assembly), charcoal canister (or charcoal canister assembly), charcoal canister vent valve (or equivalent device, such as an air pump), charcoal canister solenoid valve, connecting pipes, and the engine intake manifold. The charcoal canister absorbs gasoline vapors, preventing them from being released into the air. The charcoal canister vent valve seals the connection between the charcoal canister and the outside air and can be used to monitor for leaks in the fuel vaporization system. The charcoal canister solenoid valve controls the opening and closing of the connection between the charcoal canister and the engine intake manifold.

[0036] Engine intake manifold vacuum method: This method is used to monitor for leaks in the fuel evaporation system. By opening the charcoal canister solenoid valve and closing the charcoal canister vent valve, a negative pressure is created in the fuel tank through the engine intake manifold. If the pressure in the fuel tank does not reach a certain level of negative pressure, a large leak is identified, such as a detached pipe or a loose fuel tank cap. If a certain level of negative pressure is reached, a 1mm leak is detected. The charcoal canister solenoid valve is then closed again, creating a sealed chamber in the fuel evaporation system. The pressure in the fuel tank should rise slowly due to gasoline evaporation, with a relatively small rate of increase. If a leak of more than 1mm is present, atmospheric air enters the fuel tank rapidly, causing a faster and larger pressure rise. Therefore, different leak sizes correspond to different pressure rise rates, which are used to identify the amount of leakage in the fuel evaporation system.

[0037] The technical solutions of this disclosure and how they solve the aforementioned technical problems will be described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of this disclosure will now be described with reference to the accompanying drawings.

[0038] Vehicles equipped with gasoline engines experience significant oil vapor buildup in their fuel evaporation systems due to the volatility of gasoline. To prevent oil vapor leakage, real-time monitoring of the fuel evaporation system is necessary for timely repairs. Current methods for monitoring oil vapor leakage primarily utilize the engine intake manifold vacuum method, which determines the leakage amount based on the rate of change in air pressure within the fuel evaporation system during the monitoring period.

[0039] However, on the one hand, monitoring using the engine intake manifold vacuum method relies on the operating status of the charcoal canister solenoid valve. This is because monitoring different types of leaks requires changing the state (open or closed) of the charcoal canister solenoid valve and the charcoal canister vent valve to adjust the vacuum level in the fuel evaporation system to different states. Based on the pressure changes in the fuel evaporation system under these corresponding states, the presence of a corresponding type of leak can be determined. Therefore, the operating status of the charcoal canister solenoid valve needs to be monitored separately before monitoring. However, since the engine intake manifold vacuum method still involves the opening and closing of the charcoal canister solenoid valve, if the charcoal canister solenoid valve and the charcoal canister vent valve malfunction (e.g., intermittently stuck open or stuck closed) after monitoring (and confirming they are in normal working order), the subsequent monitoring of fuel evaporation system leaks will deviate from the actual results, leading to insufficient accuracy and reliability.

[0040] On the other hand, during vehicle operation, unstable driving conditions such as going up and down slopes, acceleration and deceleration, turning, and bumpy roads can occur, leading to phenomena such as liquid sealing of the fuel tank vent valve and fuel tank shaking. This results in a reduction of the fuel vapor space inside the fuel tank and fluctuations in fuel tank pressure, affecting the reliability of monitoring.

[0041] To address the aforementioned issues, this disclosure provides a fuel evaporation system leakage monitoring method. By simultaneously and repeatedly determining whether the charcoal canister solenoid valve and charcoal canister vent valve are in normal working order during the monitoring of different types of leaks and faults, this method effectively avoids inaccurate fuel evaporation system leakage monitoring results caused by occasional jamming or malfunctions of the charcoal canister solenoid valve or vent valve. Furthermore, it identifies issues such as the fuel tank vent valve and fuel tank swaying, and uses an exponentially weighted moving average to calculate the fuel tank pressure change rate, minimizing the impact of fuel tank pressure fluctuations during vehicle operation on monitoring. This significantly improves the accuracy and reliability of engine intake manifold vacuum monitoring.

[0042] The application scenarios of the embodiments of this disclosure are explained below:

[0043] Figure 1 This diagram illustrates an application scenario of the fuel evaporation system leakage monitoring method provided in this disclosure. Figure 1 As shown, the fuel evaporation system 100 includes a fuel tank 101, a charcoal canister 102, a charcoal canister vent valve 103, and a charcoal canister solenoid valve 104 connected in sequence. A vent shut-off valve 105 is provided at the fuel tank port. In addition, a pressure sensor 106 is provided in the fuel tank or at the connection between the fuel tank and the charcoal canister. The charcoal canister solenoid valve 104 is connected to the intake manifold 111 of the engine 110. During the fuel evaporation system leak monitoring process, by closing the charcoal canister vent valve 103 and opening the charcoal canister solenoid valve 104, the intake manifold 111 draws out the oil vapor in the fuel evaporation system 100. The pressure sensor 106 can determine whether a leak has occurred based on the monitored pressure changes.

[0044] It should be noted that, Figure 1 The scenario shown uses only one pressure sensor as an example for illustration, but this disclosure is not limited to this; that is, the number of pressure sensors can be arbitrary.

[0045] The following detailed description of the fuel evaporation system leakage monitoring method provided in this disclosure is illustrated through specific embodiments. It should be noted that the following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0046] Figure 2 A flowchart of a fuel evaporation system leakage monitoring method provided in one embodiment of this disclosure.

[0047] like Figure 2 As shown, it includes the following steps:

[0048] Step S201: In response to the satisfaction of the set monitoring conditions and vehicle status conditions, determine that the charcoal canister ventilation valve and charcoal canister solenoid valve are in normal working condition, and determine that the fuel tank has passed the first shaking degree detection.

[0049] Specifically, leak detection of the fuel evaporation system is generally carried out when the engine is running. Only when the engine is running can it draw in oil vapor from the fuel evaporation system through the engine intake manifold, and then detect leaks using the engine intake manifold vacuum method.

[0050] Therefore, before performing leak monitoring using the engine intake manifold vacuum method, it is necessary to ensure that the engine and fuel evaporation system are under the set monitoring conditions (mainly whether the equipment is working properly and whether the ambient temperature is suitable). At the same time, the vehicle's driving status is also under the corresponding vehicle status conditions (mainly whether the vehicle speed and intake manifold pressure are within the appropriate monitoring range) to ensure that the engine intake manifold vacuum method can be performed normally.

[0051] The main conditions for setting the parameters are that the engine, the relevant equipment and sensors in the fuel evaporation system are in normal condition, and the ambient temperature is not extreme, so as to ensure the accuracy of the monitoring results of the engine intake manifold vacuum method.

[0052] The vehicle status conditions mainly refer to the fact that the vehicle is in operation and that the intake manifold pressure, engine load, and vehicle speed are all within the normal range rather than extreme conditions (such as vehicle speed exceeding 150km / h or intake manifold pressure exceeding atmospheric pressure, which are all extreme conditions).

[0053] Before conducting specific leak monitoring, it is also necessary to monitor whether the charcoal canister solenoid valve, charcoal canister vent valve, etc., can be working properly to ensure that the fuel evaporation system can perform the corresponding actions normally when vacuuming is performed, thereby ensuring the reliability of the monitoring results.

[0054] Monitoring the charcoal canister solenoid valve and charcoal canister vent valve is a process that occurs before establishing a vacuum for leak detection. Therefore, by opening the charcoal canister vent valve to introduce air into the fuel vaporization system, and then observing changes in internal pressure, it can be determined whether the charcoal canister vent valve is functioning correctly. Similarly, after introducing air, the charcoal canister vent valve and charcoal canister solenoid valve can be closed, and whether the vent valve closes properly can be determined by observing whether the internal pressure rises or falls. This ensures the accuracy of subsequent leak detection.

[0055] In addition to checking the charcoal canister solenoid valve and charcoal canister vent valve, it's also necessary to ensure the vehicle is not in a state of violent shaking. Violent shaking causes drastic changes in fuel tank pressure, making it difficult to determine the actual pressure trend and leading to inaccurate monitoring results, thus hindering the accurate assessment of potential leaks in the fuel evaporation system.

[0056] The degree of sway can be monitored by measuring the rate of change of various sensors on the vehicle in directions perpendicular to the ground, the vehicle's direction of travel, and the direction perpendicular to the direction of travel. If the rate of change exceeds the set range, the sway is considered to be severe, and the subsequent monitoring process is stopped. Otherwise, the sway is determined to be within an acceptable range, and the subsequent monitoring steps continue.

[0057] Step S202: Based on the process of establishing a vacuum in the oil tank, determine that there is no liquid seal or Class I leakage in the oil tank vent shut-off valve.

[0058] The first type of leakage is used to represent the leakage situation corresponding to the leakage point with an equivalent diameter in the first numerical range.

[0059] Specifically, when monitoring the charcoal canister solenoid valve and charcoal canister vent valve, the fuel evaporation system needs to be evacuated. By observing whether the pressure in the fuel tank drops to the set value during the evacuation process, it can be determined whether there is a liquid seal in the fuel evaporation system. If there is no liquid seal, the presence of a leak can be determined based on the change in fuel tank pressure.

[0060] The liquid seal condition indicates that the vent valve in the fuel tank (the valve at the opening of the pipeline connecting the fuel tank to the charcoal canister) is submerged in fuel (i.e., liquid seal, usually caused by the vehicle driving on an inclined or bumpy road). This divides the fuel evaporation system into two parts: the fuel tank and the pipeline. This significantly reduces the space within the fuel evaporation system used for pressure change identification (i.e., the space connected to the fuel tank pressure sensor suddenly decreases). At this time, the fuel tank pressure usually changes abruptly (such as a sudden rise), leading to inaccurate leak detection.

[0061] Therefore, it is necessary to confirm that there is no liquid seal before assessing the leakage situation.

[0062] The specific method to confirm whether a liquid seal exists can be determined by whether the rate of pressure change exceeds a corresponding set threshold. If it exceeds the set threshold, it is considered that there is a sudden change in tank pressure during the vacuuming process, and a liquid seal is considered to exist. In this case, the data of the current vacuuming process is unusable, and the subsequent leakage monitoring process is stopped to ensure the reliability of the monitoring results. Conversely, if the rate of pressure change does not exceed the set threshold, it is considered that there is no liquid seal, and the subsequent monitoring process can proceed.

[0063] Because when the charcoal canister solenoid valve and charcoal canister vent valve are closed, the fuel evaporation system introduces internal gases into the engine through the intake manifold. If there is no leak, the pressure in the fuel tank should be able to drop to the set value. Unless there is a leak that allows outside air to enter the fuel evaporation system and continuously maintain the internal pressure, this can be used to determine whether there is a leak in the fuel evaporation system.

[0064] The leak identified here is a Class I leak, meaning a leak caused by a leak point with an equivalent diameter within the first numerical range. Leak points within the first numerical range are typically larger and have a greater impact on pressure changes within the fuel evaporation system. Because the pressure changes within the fuel evaporation system are quite noticeable during intake manifold vacuuming, the presence of only a small leak would not affect the overall pressure change trend within the fuel evaporation system, and it cannot be detected simply by comparing it with the set value.

[0065] Furthermore, the process of establishing a vacuum in the fuel tank can be determined by the gas flow rate entering the intake manifold from the fuel tank. If the vacuum can be established normally, the internal vacuum will inevitably reach the set range after passing through the set gas flow rate. Conversely, if there is a leak, the internal vacuum will not reach the set range even after passing through the set gas flow rate. Thus, it can be determined whether a leak exists and the vacuum establishment process is completed.

[0066] Step S203: Based on the rate of change and amount of change of fuel tank pressure during the setting process, determine that there is no charcoal canister solenoid valve malfunction or second-class leakage in the fuel evaporation system.

[0067] The second type of leakage is used to represent the leakage situation corresponding to the leakage point with an equivalent diameter in the second numerical range.

[0068] Specifically, once the vacuum is established, the operating status of the charcoal canister solenoid valve and the charcoal canister vent valve will be switched to the first preset condition. At this time, the fuel evaporation system is closed, and the pressure will slowly increase as the internal fuel evaporates. At this point, the presence of a second type of leak can be determined by the rate of change of internal pressure.

[0069] The second type of leakage is used to represent leakage caused by leak points within the second numerical range. Leak points in the second numerical range are usually small, so the corresponding leakage situation is a minor leak, that is, an inconspicuous leak. However, as long as a minor leak exists, the rate of internal pressure change will be different from the rate of internal pressure change when there is no minor leak (e.g., a greater rate of increase). Therefore, the existence of a minor leak can be determined based on the rate of internal pressure change.

[0070] Similarly, since the charcoal canister solenoid valve is activated at this time, if the charcoal canister solenoid valve malfunctions and fails to close properly, the internal pressure will continue to drop rapidly (i.e., the vacuuming process will continue). Therefore, it is also possible to simultaneously determine whether there is a charcoal canister solenoid valve stuck open.

[0071] Furthermore, while conducting Type II leak detection, a second shaking identification is also required to avoid the tank shaking violently during Type II leak detection, which would also render the monitoring results unusable (if violent shaking occurs, the subsequent monitoring process must be stopped).

[0072] Furthermore, since the operation of the charcoal canister solenoid valve is involved in the second type of leak monitoring process, and after the second type of leak monitoring is completed, it is necessary to replenish air to restore the oil tank pressure to a state of equilibrium with atmospheric pressure (so that the charcoal canister solenoid valve can be used normally after the monitoring is completed). At this time, the charcoal canister solenoid valve needs to be kept closed. Afterwards, the charcoal canister solenoid valve needs to be opened to complete the monitoring process. Therefore, after replenishing air, it is necessary to ensure that the charcoal canister solenoid valve is functioning normally again.

[0073] The air replenishment process involves closing the charcoal canister solenoid valve and opening the charcoal canister vent valve to refill the fuel vaporization system with air. This process usually lasts for a short time, such as 1 second.

[0074] After the gas replenishment process is completed, the system can be adjusted back to the first set operating condition, and the charcoal canister solenoid valve stuck and normally closed fault can be judged again based on the change in internal pressure. The principle is the same as step S201, the difference is mainly the corresponding numerical conditions, because the change in internal pressure will also be different under different internal pressure conditions.

[0075] By identifying the liquid seal and sloshing state of the fuel tank vent valve and repeatedly judging the fault of the charcoal canister solenoid valve, it is possible to effectively determine whether there are various types of leaks in the fuel evaporation system, and simultaneously eliminate the influence of faults in the charcoal canister solenoid valve and charcoal canister vent valve (if present), thereby maximizing the accuracy and reliability of the engine intake manifold vacuum method monitoring.

[0076] The fuel evaporation system leakage monitoring method provided in this disclosure determines that the charcoal canister vent valve and charcoal canister solenoid valve are in normal working condition when the set monitoring conditions and vehicle status conditions are met, and determines that the fuel tank has passed the first shaking test. Then, based on the process of establishing a vacuum in the fuel tank, it is determined that the fuel tank vent shut-off valve is free from liquid seal and first-type leakage. Based on the fuel tank pressure change rate and amount during the set process, it is determined that the fuel evaporation system is free from charcoal canister solenoid valve malfunction and second-type leakage. Therefore, it can effectively avoid the impact of unstable driving conditions on the accuracy of monitoring results. Furthermore, by monitoring different types of leaks and malfunctions in the fuel evaporation system in multiple steps, the reliability and accuracy of leakage monitoring results are maximized.

[0077] Figure 3a This is a flowchart illustrating a method for monitoring leaks in a fuel evaporation system provided in this disclosure. Figure 3a As shown, the fuel evaporation system leakage monitoring method provided in this embodiment includes the following steps:

[0078] Step S301: Determine that the set monitoring conditions and vehicle status conditions are met.

[0079] Specifically, the monitoring conditions include:

[0080] The sensors related to the fuel evaporation system are functioning normally, including the fuel tank pressure sensor, fuel tank level sensor, coolant temperature sensor, ambient temperature sensor, atmospheric pressure sensor, and engine intake manifold pressure sensor. The valves related to the fuel evaporation system are also functioning normally, including the charcoal canister solenoid valve and charcoal canister vent valve. The temperatures related to the fuel evaporation system are within their respective set ranges, including ambient temperature, coolant temperature at engine start, and the absolute value of the difference between the coolant temperature and ambient temperature at engine start. The operating status of the structures related to the fuel evaporation system is within their respective set ranges, including engine running time, total ventilation through the charcoal canister solenoid valve, and fuel level. Driving cycle monitoring of the fuel evaporation system has been completed, and there are no vehicle speed signal faults.

[0081] The normal operating state of the sensor refers to the absence of abnormal conditions such as open circuits, short power supply, short ground, or unreasonable signals.

[0082] The normal operating condition of the charcoal canister solenoid valve and the charcoal canister ventilation valve refers to the absence of abnormal conditions such as open circuit, short power supply, or short ground.

[0083] The relevant temperature mainly refers to the ambient temperature being normal (e.g., 4℃ to 35℃), the engine coolant temperature being normal (e.g., 3℃ to 38℃), and the absolute value of the difference between the coolant temperature and the ambient temperature being small when the engine starts (e.g., less than 10 degrees). At this time, the engine working pressure is low, and the working condition between the fuel evaporation system and the engine is good.

[0084] Operating status mainly refers to the engine having run for the set time (e.g., 600 seconds, at which point the engine has completed the warm-up process and the overall internal temperature is relatively stable), the fuel level not being high (e.g., below 85%, as too high a level would result in less internal gas, which could cause the fuel tank pressure sensor to be liquid-sealed, affecting the measurement results), and the total airflow through the charcoal canister solenoid valve exceeding the set amount (e.g., 8g, at which point the fuel evaporation system has also been working for some time and the overall status is relatively stable).

[0085] Driving cycle monitoring and vehicle speed signals are used to ensure that the vehicle itself can operate normally, thereby ensuring that the subsequent monitoring process can be maintained normally.

[0086] Vehicle status conditions include:

[0087] The vehicle speed is within the set speed range; the ratio of the vehicle's intake manifold pressure to atmospheric pressure is less than or equal to the set pressure ratio threshold; and the engine load is greater than or equal to the set load value.

[0088] Specifically, the set speed range varies for different vehicles, but it is usually the range of speeds that the vehicle can travel at a constant speed under non-extreme driving conditions, such as 20km / h to 120km / h.

[0089] To ensure that gases in the fuel evaporation system can be extracted through engine operation, the pressure in the engine intake manifold must be lower than atmospheric pressure. That is, the ratio of intake manifold pressure to atmospheric pressure must be less than or equal to a set pressure ratio threshold. This set pressure ratio threshold can be a number less than 1 and greater than 0, such as 0.95.

[0090] When the engine load is too low, too much extra oil vapor enters the engine and burns, which will cause abnormal engine operation. At this time, the effect of the engine extracting gas from the fuel vaporization system will be less than normal. Therefore, it is necessary to ensure that the engine is under normal engine load (i.e., greater than or equal to the set load value) to ensure that the engine operates normally.

[0091] By simultaneously ensuring that the set detection conditions and vehicle status conditions are met, the vehicle's working condition is guaranteed to be normal, all components can function properly and are in a suitable environment, thus ensuring that leak monitoring can be carried out normally and that the subsequent results are reliable.

[0092] Step S302: Based on the pressure change under the second set operating condition, determine that the charcoal canister ventilation valve is not faulty.

[0093] The second set operating condition is used to indicate that the charcoal canister solenoid valve is in the closed state and the charcoal canister ventilation valve is in the open state.

[0094] Specifically, since the pressure in the fuel evaporation system is low before monitoring begins, air needs to be introduced into it to determine if there is a significant leak, and the leak can be identified based on the pressure drop.

[0095] Therefore, it is necessary to switch the operating status of the charcoal canister solenoid valve and the charcoal canister vent valve to the second set operating condition so that air can be introduced through the charcoal canister vent valve (the process of introducing air is actually an automatic process completed under the action of pressure difference because the internal pressure is lower than the external atmospheric pressure, and it is not a process of introducing air through active equipment).

[0096] Furthermore, if the oil tank pressure value under the second set operating condition is greater than the corresponding first minimum oil tank pressure threshold, it is determined that the charcoal canister ventilation valve does not have a stuck normally closed fault.

[0097] Specifically, under the second set operating condition, the tank pressure should rapidly rise to standard atmospheric pressure (this process usually takes less than 1 second). If it is lower than standard atmospheric pressure, and the specific value is small (i.e., lower than the first minimum tank pressure threshold, such as -3 kPa), then it can be directly determined that there is a stuck normally closed charcoal canister vent valve fault, and monitoring can be terminated directly. Conversely, if the tank pressure exceeds the first minimum tank pressure threshold, it can be assumed that the charcoal canister vent valve is not stuck normally closed.

[0098] Step S303: Based on the pressure change under the first set operating condition, determine that the carbon canister solenoid valve does not have a stuck, normally open fault.

[0099] The first set operating condition is used to indicate that the charcoal canister solenoid valve and the charcoal canister ventilation valve are in the closed state.

[0100] Specifically, once the fuel tank pressure reaches or is close to the standard atmospheric pressure, the operating status of the charcoal canister solenoid valve and the charcoal canister vent valve will be switched to the first set operating condition. At this time, the internal pressure should rise slowly due to fuel evaporation. Therefore, based on the specific value of the internal pressure, it can be determined whether there is a charcoal canister solenoid valve stuck open (if so, the internal pressure of the fuel tank will drop).

[0101] Furthermore, if, after a first set operating condition and a first duration, the change in oil tank pressure exceeds the first minimum oil tank pressure change threshold, it is determined that the charcoal canister solenoid valve does not have a stuck, normally open fault.

[0102] Step S304: Based on the pressure change under the third set operating condition, determine that the carbon canister solenoid valve does not have a stuck normally closed fault.

[0103] The third setting indicates that the charcoal canister solenoid valve is in the open state and the charcoal canister ventilation valve is in the closed state.

[0104] Specifically, after confirming that the charcoal canister vent valve is not stuck and normally closed, and the charcoal canister solenoid valve is not stuck and normally open, the vacuum establishment process can begin. By closing the charcoal canister vent valve and opening the charcoal canister solenoid valve, air in the fuel evaporation system flows into the engine through the intake manifold. The pressure in the fuel evaporation system drops from slightly above atmospheric pressure to the range or set value. This process monitors for the presence of Class I leaks in the fuel evaporation system.

[0105] Since the tank pressure should drop rapidly during the vacuum building process, the presence of a stuck, normally closed charcoal canister solenoid valve can be simultaneously determined by checking whether the tank pressure change reaches the set value after a set time period (e.g., 0.5 seconds). If the tank pressure is stuck and normally closed, the tank pressure change will not reach the set value after the set time period (if the tank pressure is stuck and normally closed, the tank pressure may only drop for a short time, such as 0.1 seconds, or may not drop at all during the entire set time period).

[0106] Furthermore, if the charcoal canister flow rate reaches the first set flow rate under the third set operating condition, and the change in oil tank pressure is less than the second minimum oil tank pressure threshold, it is determined that the charcoal canister solenoid valve does not have a stuck normally closed fault.

[0107] Specifically, the process of establishing a vacuum can also be measured by setting the charcoal canister flow rate (i.e., the gas flow rate through the charcoal canister solenoid valve, which can be expressed by its weight / mass). For example, after setting the first flow rate (e.g., 1 gram), the change in tank pressure can be used to determine whether there is a stuck normally closed fault. If the charcoal canister solenoid valve is not faulty, the tank pressure will decrease as the charcoal canister flow rate increases. When the charcoal canister flow rate reaches the first set flow rate, the tank pressure should drop beyond the value corresponding to the second minimum tank pressure threshold.

[0108] Conversely, if the fuel tank pressure does not drop below the threshold after the charcoal canister flow rate reaches the first set flow rate, it indicates that during the process of reaching the first set flow rate, there is a period of time (e.g., 1 second) during which the charcoal canister solenoid valve experiences a stuck, normally closed fault. Therefore, during this period, the fuel tank pressure rises due to fuel vapor evaporation caused by the fuel evaporation system being closed (at which point both the charcoal canister solenoid valve and the charcoal canister vent valve are closed). Therefore, this can be used to determine whether a stuck, normally closed charcoal canister solenoid valve fault exists during the vacuum establishment process, thus ensuring the accuracy of the results in the subsequent leak monitoring stage.

[0109] Step S305: Based on the pressure change under the third set working condition, determine whether the oil tank has passed the first shaking degree detection.

[0110] Specifically, after the aforementioned steps have completed the testing and confirmation of the charcoal canister solenoid valve and charcoal canister ventilation valve, in order to ensure the accuracy and reliability of subsequent leak monitoring results, it is necessary to test the degree of tank shaking under the third set operating condition to ensure that the tank does not shake violently.

[0111] Furthermore, such as Figure 3b The diagram shows a flowchart for identifying the degree of tank swaying. The swaying identification includes the following steps:

[0112] Step S3051: Based on the set indicators, determine the degree of swaying of the vehicle as a whole in the corresponding direction.

[0113] The corresponding directions include those perpendicular to the chassis direction, along the driving direction, and laterally along the driving direction.

[0114] Specifically, since the shaking of the fuel tank is usually caused by the shaking of the entire vehicle, the shaking of the fuel tank can be determined by judging the shaking of the entire vehicle.

[0115] The swaying process of the fuel tank is usually a relatively complex motion process, such as frequent changes in position in multiple directions at the same time. Therefore, the swaying process of the fuel tank can be substituted into a three-dimensional coordinate system centered on the vehicle, and the overall swaying of the vehicle can be determined based on the swaying along each coordinate axis.

[0116] The specific coordinate axis direction can be selected as perpendicular to the chassis direction (that is, the vertical direction or z-axis direction in the coordinate axis), along the driving direction (that is, the parallel direction or y-axis direction in the coordinate axis), and laterally along the driving direction (that is, the vertical direction or x-axis direction in the coordinate axis). By determining the vehicle swaying in these three directions respectively, the overall vehicle swaying can be obtained.

[0117] To determine the vehicle's swaying in each direction, different indicators can be selected. For example, perpendicular to the chassis, the vertical acceleration detected by the vehicle's overall acceleration sensor can be used. The swaying in this direction can be determined based on the change in velocity along the vertical direction, as a large acceleration in this direction indicates that the vehicle is in an environment of up-and-down bumps. Similarly, for the lateral direction of travel, the rate of change of steering wheel rotation speed can be used to determine whether the vehicle is swaying in this direction, because when the steering wheel is turned suddenly and quickly, the vehicle will accelerate laterally, which usually results in lateral swaying. For the direction of travel, the rate of change of throttle opening or accelerator opening can be used to determine whether the vehicle is swaying in this direction, because when the throttle or accelerator is opened and closed quickly, the vehicle will accelerate or decelerate, which usually results in swaying along the direction of travel.

[0118] Step S3052: Determine the maximum value of the vehicle's sway in each corresponding direction as the sway level of the fuel tank.

[0119] Specifically, since any shaking in any direction corresponds to shaking of the fuel tank, when the degree of shaking in any direction reaches the preset level of violent shaking, it can be considered that the degree of shaking of the fuel tank has reached the standard of violent shaking. At this point, the leak detection process should not continue, because the accuracy of the measurement results cannot be guaranteed.

[0120] Similarly, if the degree of shaking in any direction is low, it can be directly assumed that the degree of shaking in the fuel tank is low. In this case, the leak detection process can continue because the measurement results are less affected by the shaking of the fuel tank, and the accuracy of the measurement results can be guaranteed.

[0121] Step S306: If the charcoal canister flow rate reaches the second set flow rate under the third set operating condition, and the change in fuel tank pressure is less than the third minimum fuel tank pressure threshold, it is determined that there is no fault of the fuel tank cap not being tightened in the fuel evaporation system.

[0122] Specifically, since it has been determined in the aforementioned steps that the charcoal canister vent valve and charcoal canister solenoid valve are not faulty, if the change in fuel tank pressure is lower than the set value (i.e., the third minimum fuel tank pressure threshold), it can be determined that there is a fault of the fuel tank cap not being tightened or other valves or caps that can allow outside air to enter the fuel evaporation system (only if outside air can still enter the fuel evaporation system, or if there is a leak, will the change in pressure of the fuel evaporation system be lower than expected).

[0123] Therefore, a second set flow rate (e.g., 2.5 grams) can be set as a stage condition for monitoring whether there is a fault in the fuel tank cap not being tightened. This allows for further elimination of faults in the fuel evaporation system structure and assembly, such as the fuel tank cap, after ruling out faults in the charcoal canister vent valve and charcoal canister solenoid valve. This ensures the accuracy and reliability of subsequent leak monitoring to the greatest extent possible.

[0124] Step S307: If the charcoal canister flow rate reaches the third set flow rate under the third set operating condition, and the change in fuel tank pressure is less than the fourth minimum fuel tank pressure threshold, it is determined that there is no first-type leakage in the fuel evaporation system, and the vacuum establishment process is completed.

[0125] The third set flow rate is greater than the second set flow rate.

[0126] Specifically, after completing the fault monitoring of the relevant structures, the vacuum level can be established, and based on the vacuum level establishment results, it can be determined whether there is a Type I leak in the fuel tank. Type I leaks mainly refer to leaks at points with an equivalent diameter within a certain range. This range typically represents larger leaks, such as leaks with an equivalent diameter greater than 2.2 mm. Such leaks allow a continuous influx of air into the fuel evaporation system, resulting in a relatively high fuel tank pressure even under the third set operating condition. In this case, regardless of the gas flow rate discharged from the charcoal canister solenoid valve, the internal pressure usually cannot reach the set low value.

[0127] At this point, the relationship between the reduction amount and the set value can also be used to represent it. If the pressure change is less than the fourth lowest fuel tank pressure threshold (usually a negative number, such as -1.5 kPa), that is, the pressure change is negative and the absolute value of the pressure change is greater than the absolute value of the fourth lowest fuel tank pressure threshold, it can be determined that the internal pressure of the fuel evaporation system has reached the set low value (since the fuel evaporation system structure of different models is different, the internal pressure low value corresponding to its vacuum degree is not uniform. Therefore, the change amount can be used to uniformly describe the process of establishing vacuum degree, because vacuum degree is a change amount relative to atmospheric pressure. As long as the vacuum degree reaches a certain level, it can be considered that the vacuum degree has been successfully established), and thus it can be determined that the vacuum degree has been successfully established.

[0128] Step S308: Based on the pressure change rate under the third set operating condition, determine that there is no liquid seal in the oil tank vent shut-off valve.

[0129] Specifically, while ruling out the first type of leakage, it is also necessary to ensure that there is no liquid seal on the oil tank vent shut-off valve to guarantee the reliability of the data on which the leakage monitoring is based.

[0130] Furthermore, such as Figure 3c The flowchart shown is for determining the liquid seal status of the fuel tank vent shut-off valve, and it specifically includes the following steps:

[0131] Step S3081: If the third set operating condition is in effect, obtain the rate of change of the oil tank pressure until the charcoal canister flow rate reaches the third set flow rate.

[0132] Specifically, after completing the monitoring of the stuck normally closed charcoal canister solenoid valve, the fuel evaporation system will continue to build up a vacuum under the third set operating condition. During the vacuum building process, it will ensure that there is no liquid seal in the fuel tank to ensure data accuracy. Then, it will monitor the fuel evaporation system again for other faults, such as the fuel tank cap not being tightened.

[0133] During the vacuuming process, the air pressure inside the fuel evaporation system continuously decreases. If there is a leak in the fuel evaporation system, the gas pressure change will differ from that when there is no leak. However, if the vehicle is on an inclined road and there is a lot of fuel in the tank (such as when the fuel level reaches more than 70%), the gasoline in the tank may liquid seal the vent valve under the influence of gravity. This causes the space connected to the pressure sensor to shrink instantaneously, resulting in a sudden change in gas pressure or an excessively rapid decrease in pressure. Therefore, the presence of a liquid seal can be determined based on the instantaneous change in gas pressure or the overall rate of change, i.e., the pressure change rate.

[0134] Step S3082: If the rate of pressure change meets the set conditions, determine that there is no liquid seal in the oil tank vent shut-off valve.

[0135] Specifically, since the rate of pressure change can be represented by different indicators, such as the extreme value of the rate of pressure drop or the variance, there are also different setting conditions to determine whether a liquid seal exists.

[0136] The set condition is used to indicate that the instantaneous change in the rate of pressure drop exceeds the set standard. At this time, it can be determined that it is caused by the space connected to the pressure sensor being too small. The only reason that would cause this space to be too small is usually a liquid seal. Therefore, it can be determined that a liquid seal is present.

[0137] Step S309: Based on the rate of change of fuel tank pressure under the first set operating condition, determine that there is no charcoal canister solenoid valve malfunction in the fuel evaporation system.

[0138] Specifically, before determining whether a second type of leakage exists, it is essential to ensure that the activation of the charcoal canister solenoid valve during previous testing did not cause it to malfunction, in order to guarantee the accuracy of the assessment results.

[0139] Furthermore, such as Figure 3d The flowchart shown is for determining whether there is a charcoal canister solenoid valve malfunction in the fuel evaporation system under the first set operating condition. The steps include:

[0140] Step S3091: In response to the completion of the vacuum establishment process, determine the duration during which the fuel evaporation system is in the first set operating condition reaches the first duration.

[0141] Specifically, after the vacuum is established, the system can be monitored for Type II leaks in the fuel evaporation system. Type II leaks are caused by minute leaks (leaks with an equivalent diameter smaller than the first set range). These leaks are relatively minor, and switching from the vacuum-established state to the first set operating condition requires changing the operating state of the charcoal canister solenoid valve. Therefore, while monitoring for Type II leaks, it is also necessary to ensure that the charcoal canister solenoid valve is not stuck or permanently open, to avoid the leak monitoring results becoming invalid due to the solenoid valve failing to complete the switching of its operating state properly.

[0142] To determine whether there is a charcoal canister solenoid valve malfunction or a second type of leakage, the rate of change of fuel tank pressure within a set time period (i.e., the first time period) is used. Therefore, it is necessary to maintain the fuel evaporation system under the first set operating condition for the first time period for subsequent analysis.

[0143] Step S3092: If the rate of increase of the fuel tank pressure within the first time period is greater than the first rate of increase threshold, it is determined that there is no stuck open fault of the charcoal canister solenoid valve in the fuel evaporation system.

[0144] Specifically, if there is no charcoal canister solenoid valve malfunction in the fuel evaporation system, it will be a closed space under the first set operating condition. The fuel tank pressure will rise slowly due to gas evaporation. If the fuel tank pressure rise rate is small (e.g., less than the first rise rate threshold), it indicates that gas in the fuel tank is still continuously flowing out. At this time, it is only possible that the charcoal canister solenoid valve is stuck and normally open, causing the internal gas to continue to flow into the engine intake manifold. Therefore, the working status of the charcoal canister solenoid valve under the first set operating condition can be determined based on this, ensuring the accuracy of monitoring the second type of leakage.

[0145] Step S310: Record the rate of change of oil tank pressure and determine the degree of shaking of the oil tank within the first time period.

[0146] Specifically, after troubleshooting the stuck normally open charcoal canister solenoid valve, another test is needed after the subsequent air replenishment process. Therefore, it is necessary to record the rate of change of oil tank pressure obtained in the first time period, and then perform the calculation after confirming that the charcoal canister solenoid valve is fault-free.

[0147] Furthermore, since it is necessary to monitor subtle changes in the tank pressure during this period to determine whether there is a second type of leakage, and since the second type of leakage is relatively minor, it is necessary to ensure that the tank does not shake violently during this process.

[0148] The specific method for monitoring the degree of swaying is the same as in step S305, and will not be repeated here.

[0149] In some embodiments, the rate of change of tank pressure can be calculated using an Exponentially Weighted Moving-Average (EWMA) algorithm, the specific calculation method of which is as follows: Figure 3e As shown, this is a schematic diagram of a method for determining the rate of change of tank pressure based on the EWMA algorithm. The calculation process specifically includes the following steps:

[0150] Step S3101: Obtain the oil tank pressure sampling data within the first time period.

[0151] Specifically, if the vehicle is driving on inclines or declines, accelerations or decelerations, turns, or bumpy roads, even if the fuel tank does not shake violently, slight shaking may cause the space connected to the pressure sensor to fluctuate. In this case, it is impossible to accurately determine whether there is a leak by the instantaneous value of the fuel tank pressure, because the instantaneous pressure value may fluctuate quite violently, resulting in a deviation between the calculation result and the actual situation.

[0152] Therefore, the pressure changes within the first time period can be divided into multiple time periods of a set length (i.e., set sampling time periods), calculated separately, and the rate of change of tank pressure can be determined by comparing the overall pressure changes in each time period, thereby determining whether there is a leak; alternatively, each sampling time period can be further divided and calculated.

[0153] Since the instantaneous pressure inside the fuel tank may change continuously when the tank shakes, the fuel tank pressure data within the first time period can be sampled. By using the sampled fuel tank pressure data for calculation, the impact of fuel tank pressure signal fluctuations caused by the tank shaking can be effectively reduced, thereby improving the robustness and reliability of the calculation results.

[0154] Step S3102: Based on the oil tank pressure sampling data, determine the pressure change within the first time period.

[0155] The pressure change includes the rate of pressure change.

[0156] Specifically, because the pressure in a swaying fuel tank is usually in a state of continuous change (it may rise, fall, or become negative), even data sampling cannot eliminate the characteristic of continuous pressure change. Therefore, when describing pressure changes, the rate of pressure change is usually used directly instead of the specific pressure value. This is because if the fuel tank pressure simply fluctuates without leakage, the rate of pressure change will have both rising and falling values, and the overall pressure will remain relatively balanced.

[0157] However, if a specific pressure value is chosen to describe the pressure, there may be situations where the instantaneous pressure is extremely high (such as when the fuel tank shakes, causing the space adjacent to the pressure sensor to be squeezed by the fuel, forming a temporary high-pressure sealed space), which makes it difficult to assess the actual pressure changes based on the measurement results.

[0158] When evaluating pressure changes within each sampling period, either the average pressure change rate or the average pressure change rate within that period can be chosen. However, extreme values ​​of the pressure change rate are typically avoided. This is because, given fluctuations in tank pressure, the extreme values ​​of the pressure change rate within each sampling period may coincide with the actual pressure values, resulting in extremely high instantaneous pressure change rates. This makes it difficult to assess the actual pressure changes based on the calculation results.

[0159] Furthermore, the rate of pressure change can be calculated using the following formula:

[0160]

[0161] Where, ΔP n P is used to represent the rate of pressure change. n,1 P n,2 These represent the tank pressure sampling data at two adjacent sampling times, and Δt represents the time difference between two adjacent sampling times (usually a fixed value, such as 10 milliseconds).

[0162] Step S3103: If the pressure change meets the set conditions, determine the oil tank pressure rise rate based on the exponentially weighted moving average of the pressure change rate within the first time period.

[0163] Specifically, the setting conditions vary depending on the specific indicator used to represent the pressure changes within each sampling period.

[0164] Typically, the setting conditions are threshold values ​​corresponding to different specific indicators. For example, if the specific indicator is the average rate of pressure change, the setting condition can be that the average rate of pressure change does not exceed a set average threshold. If the pressure change meets this setting condition, it indicates that the pressure fluctuation in the tank is within an acceptable range, and the corresponding pressure change state indicator can be calculated based on the specific indicator.

[0165] The method for calculating the exponentially weighted moving average (EWMA) value for the current sampling period is as follows: based on a set exponent, the average rate of pressure change within the current sampling period is multiplied by the exponent, and then this product is added to the product of the EWMA value calculated for the previous sampling periods and the exponent. This ensures that the EWMA values ​​calculated for each sampling period collectively reflect the tank pressure change status, guaranteeing the reliability of the results.

[0166] Since the EWMA value for each time period reflects the average rate of pressure change in each sampling time period, the EWMA value for each sampling time period within the first time period can be directly used as the corresponding rate of change of tank pressure within the first time period for subsequent evaluation.

[0167] Step S311: In response to the completion of the air replenishment process in the fuel tank, based on the change in fuel tank pressure under the first set operating condition, determine that there is no charcoal canister solenoid valve malfunction in the fuel evaporation system.

[0168] The process of replenishing air in the fuel tank is used to indicate the process of increasing the pressure in the fuel tank within a set time period.

[0169] Specifically, after completing the second shaking test, the fuel tank pressure needs to be increased to a range that is the same as or similar to the outside air pressure by adding air, so that the fuel evaporation system can work normally directly after the monitoring is completed.

[0170] Specifically, such as Figure 3f The diagram shows a flowchart for replenishing air and troubleshooting a charcoal canister solenoid valve malfunction, which includes the following steps:

[0171] Step S3111: Determine the duration for which the fuel evaporation system is in the second set operating condition, and complete the fuel tank replenishment process.

[0172] Specifically, since the charcoal canister solenoid valve closed during the detection of the second type of leak, the accuracy of the result may not be guaranteed by a single judgment. Therefore, it is necessary to adjust the internal pressure of the fuel evaporation system and make a second judgment on the charcoal canister solenoid valve malfunction.

[0173] The method for adjusting the internal pressure of the fuel evaporation system is to replenish the fuel tank with air. By switching back to the second set operating condition, outside air can enter the fuel evaporation system through the charcoal canister vent valve, quickly increasing the pressure of the fuel evaporation system. Since outside air can increase the fuel tank pressure to atmospheric pressure at a relatively fast rate under atmospheric pressure, the air replenishment process can be selected for a shorter duration (i.e., the second duration, which can be 1 second, 0.5 seconds, or other durations).

[0174] Step S3112: In response to the completion of the air replenishment process in the fuel tank, determine the duration during which the fuel evaporation system is in the first set operating condition reaches the first duration.

[0175] Specifically, after completing the gas replenishment process, monitoring can be performed again to troubleshoot the stuck, normally open charcoal canister solenoid valve. The specific principle of this step is the same as that of step S3101, and will not be repeated here.

[0176] Step S3113: If the change in fuel tank pressure within the first time period is greater than the second minimum fuel tank change threshold, it is determined that there is no stuck open fault in the charcoal canister solenoid valve in the fuel evaporation system.

[0177] Specifically, unlike step S3092 where the oil tank pressure change rate is monitored during the charcoal canister solenoid valve fault monitoring, this step uses the amount of oil tank pressure change to determine whether there is a charcoal canister solenoid valve stuck open fault. If the amount of oil tank pressure change is greater than the corresponding threshold (i.e., the second minimum oil tank change threshold, such as -0.1kPa or 0kPa), it indicates that the oil tank pressure is in an upward state under the first set operating condition, and the charcoal canister solenoid valve stuck open fault can be ruled out.

[0178] Step S312: Based on the recorded rate of change of fuel tank pressure, determine that there is no Type II leakage in the fuel evaporation system.

[0179] Among them, the maximum value of the second numerical range corresponding to the second type of leakage is less than the minimum value of the first numerical range corresponding to the first type of leakage.

[0180] Specifically, if the rate of increase in tank pressure within the first recorded time period is less than the second rate of increase threshold, it is determined that there is no second type of leakage in the fuel evaporation system.

[0181] If the charcoal canister solenoid valve is functioning properly and there is no Type I leakage in the fuel evaporation system, the recorded fuel tank pressure change rate can indicate an increase in the internal air pressure of the fuel evaporation system. However, the increase is limited in a short period of time (e.g., within 1 second). If the fuel tank pressure increase rate (maximum fuel tank pressure) exceeds the second pressure increase rate threshold within the first time period, it indicates that in addition to the evaporation of internal gas, there are other factors causing the internal gas pressure to rise, meaning there must be a leakage. Therefore, this can be used to determine whether there is a Type II leakage.

[0182] The equivalent diameter of the leakage hole corresponding to the second type of leakage is relatively small, usually only about 1 mm.

[0183] Step S313: Adjust both the charcoal canister ventilation valve and the charcoal canister solenoid valve to the open position to end the leak monitoring process.

[0184] Specifically, after monitoring is completed, the charcoal canister vent valve and charcoal canister solenoid valve can be restored to the open state so that their working status can be properly controlled during subsequent engine operation.

[0185] In some embodiments, if it is determined that the set monitoring conditions or vehicle status conditions are not met, or the charcoal canister ventilation valve or charcoal canister solenoid valve is not in normal working condition, the subsequent steps are stopped and the leakage monitoring process ends.

[0186] Specifically, in combination Figure 3g The diagram illustrates the correspondence between each step of leak monitoring and the fuel tank pressure. The horizontal axis represents time and monitoring stages, with dashed lines distinguishing the monitoring stages for each step (the order of steps within the same two dashed lines can be interchanged without strict limitation). The vertical axis represents fuel tank pressure: 0 represents standard atmospheric pressure, above 0 is positive pressure exceeding standard atmospheric pressure, and below 0 is negative pressure. t1 represents the first duration, and t2 represents the second duration. If any monitoring indicator fails to meet the corresponding monitoring conditions in any step, or if any valve, fuel tank cap, etc., is found to be faulty, subsequent detection steps are immediately stopped, and the results are reported to the vehicle control unit for timely repair or handling to ensure vehicle safety.

[0187] The fuel evaporation system leakage monitoring method provided in this disclosure first performs fault detection on the charcoal canister vent valve and charcoal canister solenoid valve. After confirming that they are fault-free, a vacuum is established. Under the premise of ensuring no severe fuel tank shaking, the method eliminates charcoal canister solenoid valve malfunctions, fuel tank cap malfunctions, and first-type leakage conditions. Then, under different pressure conditions and using different indicators, the method detects the presence of charcoal canister solenoid valve malfunctions twice. After repeatedly confirming that the charcoal canister solenoid valve is not faulty, the method then determines second-type leakage conditions. Simultaneously, it ensures that the results are not affected by severe fuel tank shaking, vent valve liquid seals, etc. Therefore, by combining different set operating conditions and different indicators, the method progressively tests each component of the fuel evaporation system under different environments. Under the premise of eliminating the influence of severe fuel tank shaking, vent valve liquid seals, etc., the method detects malfunctions ranging from obvious faults that have a significant impact on the vehicle (such as fuel tank cap malfunctions), large leaks (such as first-type leaks), to minor leaks (such as second-type leaks). This effectively ensures that when an anomaly is found in any component, no larger fault goes undetected, thereby ensuring the overall safety of the vehicle.

[0188] Figure 4 This is a schematic diagram of a fuel evaporation system leak monitoring device provided in this disclosure. Figure 4 As shown, the fuel evaporation system leak monitoring device 400 includes: a condition judgment module 410, a first monitoring module 420, and a second monitoring module 430. Wherein:

[0189] The condition judgment module 410 is used to determine that the charcoal canister ventilation valve and the charcoal canister solenoid valve are in normal working condition in response to the satisfaction of the set monitoring conditions and vehicle status conditions, and to determine that the fuel tank has passed the first shaking degree detection.

[0190] The first monitoring module 420 is used to determine whether there is a liquid seal or a first type of leakage condition in the oil tank vent shut-off valve based on the process of establishing a vacuum in the oil tank. The first type of leakage condition is used to indicate the leakage condition corresponding to the leakage point with an equivalent diameter in the first numerical range.

[0191] The second monitoring module 430 is used to determine, based on the rate of change of fuel tank pressure and the amount of change of fuel tank pressure during the set process, that there is no charcoal canister solenoid valve failure or second type of leakage in the fuel evaporation system. The second type of leakage is used to indicate the leakage situation corresponding to the leakage point with an equivalent diameter in the second numerical range.

[0192] Optionally, the condition judgment module 410 specifically includes setting monitoring conditions including: the sensors related to the fuel evaporation system are in normal working condition, including the fuel tank pressure sensor, fuel tank fuel level sensor, coolant temperature sensor, ambient temperature sensor, atmospheric pressure sensor, and engine intake manifold pressure sensor; the valves related to the fuel evaporation system are in normal working condition, including the charcoal canister solenoid valve and the charcoal canister vent valve; the temperatures related to the fuel evaporation system are within the corresponding set range, including the ambient temperature, the coolant temperature when the engine starts, and the absolute value of the difference between the coolant temperature and the ambient temperature when the engine starts; the operating status of the structures related to the fuel evaporation system is within the corresponding set value range, including the engine running time, the total ventilation volume through the charcoal canister solenoid valve, and the fuel level; and the driving cycle monitoring of the fuel evaporation system has been completed and there is no vehicle speed signal fault.

[0193] Optionally, the condition judgment module 410 specifically includes vehicle status conditions including: the vehicle speed is within a set speed range; the ratio of the vehicle's intake manifold pressure to atmospheric pressure is less than or equal to a set pressure ratio threshold; and the engine load is greater than or equal to a set load value.

[0194] Optionally, the condition judgment module 410 is specifically used to: determine, based on the pressure change under the second set operating condition, that the charcoal canister vent valve is not faulty; the second set operating condition indicates that the charcoal canister solenoid valve is in the closed state and the charcoal canister vent valve is in the open state; determine, based on the pressure change under the first set operating condition, that the charcoal canister solenoid valve is not stuck and normally open; determine, based on the pressure change under the third set operating condition, that the charcoal canister solenoid valve is not stuck and normally closed; the third set operating condition indicates that the charcoal canister solenoid valve is in the open state and the charcoal canister vent valve is in the closed state; and determine, based on the pressure change under the third set operating condition, that the oil tank has passed the first shaking degree detection.

[0195] Optionally, the condition judgment module 410 is specifically used to determine that the charcoal canister ventilation valve does not have a stuck normally closed fault if the oil tank pressure value under the second set working condition is greater than the corresponding first minimum oil tank pressure threshold.

[0196] Optionally, the condition judgment module 410 is specifically used to determine that the charcoal canister solenoid valve does not have a stuck normally open fault if, after a first set working condition and a first time period, the change in oil tank pressure is greater than the first minimum oil tank pressure change threshold.

[0197] Optionally, the condition judgment module 410 is specifically used to determine that the charcoal canister solenoid valve does not have a stuck normally closed fault if the charcoal canister flow rate reaches the first set flow rate under the third set operating condition and the oil tank pressure change is less than the second minimum oil tank pressure threshold.

[0198] Optionally, the first monitoring module 420 is specifically used to: if the charcoal canister flow rate under the third set operating condition reaches the second set flow rate, and the change in fuel tank pressure is less than the third minimum fuel tank pressure threshold, determine that there is no fault of the fuel tank cap not being tightened in the fuel evaporation system; if the charcoal canister flow rate under the third set operating condition reaches the third set flow rate, and the change in fuel tank pressure is less than the fourth minimum fuel tank pressure threshold, determine that there is no first-type leakage in the fuel evaporation system, complete the vacuum establishment process, and the third set flow rate is greater than the second set flow rate; and determine that there is no liquid seal in the fuel tank vent shut-off valve based on the pressure change rate under the third set operating condition.

[0199] Optionally, the first monitoring module 420 is specifically used to: if under the third set operating condition, acquire the pressure change rate of the oil tank pressure until the charcoal canister flow rate reaches the third set flow rate; if the pressure change rate meets the set conditions, determine that there is no liquid seal in the oil tank vent shut-off valve.

[0200] Optionally, the second monitoring module 430 is specifically used to: determine, based on the rate of change of fuel tank pressure under the first set operating condition, that there is no charcoal canister solenoid valve malfunction in the fuel evaporation system; record the rate of change of fuel tank pressure and determine that the fuel tank has passed the second shaking degree detection; in response to the process of completing the air replenishment in the fuel tank, determine, based on the amount of change of fuel tank pressure under the first set operating condition, that there is no charcoal canister solenoid valve malfunction in the fuel evaporation system, the process of completing the air replenishment in the fuel tank being used to represent the process of raising the pressure in the fuel tank within a set time period; and determine, based on the recorded rate of change of fuel tank pressure, that there is no second type of leakage in the fuel evaporation system.

[0201] Optionally, the second monitoring module 430 is specifically used to, in response to the completion of the vacuum establishment process, determine that the duration of the fuel evaporation system under the first set operating condition has reached a first duration; determine that the fuel tank passes the second shaking degree detection within the first duration; and if the fuel tank pressure rise rate within the first duration is greater than the first rise rate threshold, determine that there is no charcoal canister solenoid valve stuck open fault in the fuel evaporation system.

[0202] Optionally, the second monitoring module 430 is specifically used to determine the duration of the fuel evaporation system being in the second set operating condition, and to complete the gas replenishment process in the fuel tank.

[0203] Optionally, the second monitoring module 430 is specifically used to determine, in response to the completion of the gas replenishment process in the fuel tank, the duration of the fuel evaporation system under the first set operating condition reaches the first duration; if the change in fuel tank pressure within the first duration is greater than the second minimum fuel tank change threshold, it is determined that there is no charcoal canister solenoid valve stuck open fault in the fuel evaporation system.

[0204] Optionally, the second monitoring module 430 is specifically used to determine that there is no second type of leakage in the fuel evaporation system if the rate of increase of the fuel tank pressure within the first recorded time period is less than the second rate of increase threshold.

[0205] Optionally, the second monitoring module 430 is specifically used to obtain the rate of change of the tank pressure in the following manner: acquiring tank pressure sampling data within a first time period; determining the pressure change within the first time period based on the tank pressure sampling data, including the rate of pressure change; and if the pressure change meets the set conditions, determining the rate of increase of the tank pressure based on the exponentially weighted moving average of the rate of pressure change within the first time period.

[0206] Optionally, the condition judgment module 410 and the second monitoring module 430 are specifically used to determine the degree of swaying of the vehicle as a whole in the corresponding direction based on the set indicators. The corresponding direction includes the direction perpendicular to the chassis, the direction of travel, and the lateral direction of travel. The maximum value of the degree of swaying of the vehicle in each corresponding direction is determined as the degree of swaying of the fuel tank.

[0207] Optionally, the second monitoring module 430 is further configured to, based on the rate of change of fuel tank pressure and the amount of change of fuel tank pressure during the setting process, determine that there is no charcoal canister solenoid valve failure or second-class leakage in the fuel evaporation system, and then adjust both the charcoal canister vent valve and the charcoal canister solenoid valve to the open state, thereby ending the leakage monitoring process.

[0208] Optionally, the fuel evaporation system leak monitoring device 400 also includes the option to stop subsequent steps and end the leak monitoring process if it is determined that the set monitoring conditions or vehicle status conditions are not met, or the charcoal canister vent valve or charcoal canister solenoid valve is not in normal working condition.

[0209] In this embodiment, the fuel evaporation system leak monitoring device, through the combination of various modules, can effectively avoid the impact of unstable driving conditions on the accuracy of monitoring results. At the same time, by monitoring different types of leaks and faults in the fuel evaporation system in multiple steps, the reliability and accuracy of leak monitoring results are maximized.

[0210] Figure 5 This is a schematic diagram of the structure of a control device provided in this disclosure, such as... Figure 5 As shown, the control device 500 includes a memory 510 and a processor 520.

[0211] The memory 510 stores a computer program that can be executed by at least one processor 520. This computer program is executed by at least one processor 520 to enable the control device to implement the fuel vaporization system leak monitoring method provided in any of the above embodiments.

[0212] The memory 510 and the processor 520 can be connected via a bus 530.

[0213] The relevant explanations can be understood by referring to the corresponding descriptions and effects in the method embodiments, and will not be repeated here.

[0214] One embodiment of this disclosure provides a computer-readable storage medium having a computer program stored thereon, the computer program being executed by a processor to perform the following: Figures 2 to 3g The corresponding embodiment of the fuel evaporation system leakage monitoring method.

[0215] The computer-readable storage medium may be ROM, random access memory (RAM), CD-ROM, magnetic tape, floppy disk, and optical data storage device, etc.

[0216] One embodiment of this disclosure provides a computer program product comprising computer-executable instructions that, when executed by a processor, are used to perform, as follows: Figures 2 to 3g The corresponding embodiment of the fuel evaporation system leakage monitoring method.

[0217] In the several embodiments provided in this disclosure, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0218] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following claims.

[0219] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A method for monitoring leaks in a fuel evaporation system, characterized in that, The method includes: In response to the fulfillment of the set monitoring conditions and vehicle status conditions, it is determined that the charcoal canister ventilation valve and charcoal canister solenoid valve are in normal working condition, and the fuel tank passes the first shaking degree detection. Based on the process of establishing a vacuum in the oil tank, it is determined that there is no liquid seal or first type of leakage in the oil tank vent shut-off valve. The first type of leakage is used to indicate the leakage situation corresponding to the leakage point with an equivalent diameter in the first numerical range. Based on the rate and amount of change of tank pressure during the setting process, it is determined that there is no charcoal canister solenoid valve failure or second type of leakage in the fuel evaporation system. The second type of leakage is used to represent the leakage situation corresponding to the leakage point with an equivalent diameter in the second numerical range. Based on the rate and amount of change in tank pressure during the set process, it is determined that there is no charcoal canister solenoid valve malfunction or second-type leakage in the fuel evaporation system, including: Based on the rate of change of fuel tank pressure under the first set operating condition, it is determined that there is no charcoal canister solenoid valve malfunction in the fuel evaporation system. Record the rate of change of the oil tank pressure and determine the extent of the second shaking test of the oil tank; In response to the completion of the air replenishment process in the fuel tank, based on the change in fuel tank pressure under the first set operating condition, it is determined that there is no charcoal canister solenoid valve malfunction in the fuel evaporation system. The completion of the air replenishment process in the fuel tank is used to represent the process of raising the pressure in the fuel tank within a set time period. Based on the recorded rate of change of fuel tank pressure, it is determined that there is no type II leakage in the fuel evaporation system.

2. The method for monitoring fuel evaporation system leaks according to claim 1, characterized in that, The set monitoring conditions include: The sensors related to the fuel evaporation system are in normal working condition. These sensors include a fuel tank pressure sensor, a fuel tank fuel level sensor, a coolant temperature sensor, an ambient temperature sensor, an atmospheric pressure sensor, and an engine intake manifold pressure sensor. The valves related to the fuel evaporation system are in normal working condition. The valves related to the fuel evaporation system include the charcoal canister solenoid valve and the charcoal canister vent valve. The relevant temperature of the fuel evaporation system is within a corresponding set range. The relevant temperature of the fuel evaporation system includes the ambient temperature, the coolant temperature when the engine is started, and the absolute value of the difference between the coolant temperature and the ambient temperature when the engine is started. The operating status of the relevant structures of the fuel evaporation system is within the corresponding set value range. The operating status includes engine running time, total air flow through the charcoal canister solenoid valve, and fuel level. The driving cycle monitoring of the fuel evaporation system has been completed and there is no vehicle speed signal fault.

3. The method for monitoring fuel evaporation system leaks according to claim 1, characterized in that, The vehicle status conditions include: The vehicle's speed is within the set speed range; The ratio of the vehicle's intake manifold pressure to atmospheric pressure is less than or equal to a set pressure ratio threshold. The engine load is greater than or equal to the set load value.

4. The method for monitoring fuel evaporation system leaks according to claim 1, characterized in that, The process of determining that the charcoal canister ventilation valve and the charcoal canister solenoid valve are in normal working condition, and determining that the fuel tank has passed the first shaking test, includes: Based on the pressure changes under the second set operating condition, it is determined that the charcoal canister ventilation valve is not faulty. The second set operating condition is used to indicate that the charcoal canister solenoid valve is in the closed state and the charcoal canister ventilation valve is in the open state. Based on the pressure change under the first set operating condition, it is determined that the charcoal canister solenoid valve does not have a stuck open fault. The first set operating condition is used to indicate that the charcoal canister solenoid valve and the charcoal canister ventilation valve are in the closed state. Based on the pressure change under the third set operating condition, it is determined that the charcoal canister solenoid valve does not have a stuck normally closed fault. The third set operating condition is used to indicate that the charcoal canister solenoid valve is in the open state and the charcoal canister ventilation valve is in the closed state. Based on the pressure change under the third set operating condition, the degree of shaking of the oil tank is determined to be detected for the first time.

5. The method for monitoring leaks in a fuel evaporation system according to claim 4, characterized in that, The determination that the charcoal canister ventilation valve is not faulty based on the pressure changes under the second set operating condition includes: If the oil tank pressure value under the second set operating condition is greater than the corresponding first minimum oil tank pressure threshold, it is determined that the charcoal canister ventilation valve does not have a stuck normally closed fault.

6. The method for monitoring leaks in a fuel evaporation system according to claim 4, characterized in that, The determination that the charcoal canister solenoid valve does not have a stuck, normally open fault based on the pressure change under the first set operating condition includes: If, after a first set operating condition and a first duration, the change in oil tank pressure exceeds the first minimum oil tank pressure change threshold, it is determined that the charcoal canister solenoid valve does not have a stuck, normally open fault.

7. The method for monitoring leaks in a fuel evaporation system according to claim 4, characterized in that, The determination that the charcoal canister solenoid valve does not have a stuck, normally closed fault based on the pressure change under the third set operating condition includes: If the charcoal canister flow rate reaches the first set flow rate under the third set operating condition, and the change in oil tank pressure is less than the second minimum oil tank pressure threshold, it is determined that the charcoal canister solenoid valve does not have a stuck normally closed fault.

8. The method for monitoring fuel evaporation system leaks according to claim 1, characterized in that, The process of establishing a vacuum in the fuel tank, and determining that the fuel tank vent valve is free from liquid seal and Class I leakage, includes: If the flow rate of the charcoal canister reaches the second set flow rate under the third set operating condition, and the change in fuel tank pressure is less than the third minimum fuel tank pressure threshold, it is determined that the fuel evaporation system does not have a fault of the fuel tank cap not being tightened. If the carbon canister flow rate under the third set operating condition reaches the third set flow rate, and the change in fuel tank pressure is less than the fourth minimum fuel tank pressure threshold, it is determined that there is no first type of leakage in the fuel evaporation system, and the vacuum establishment process is completed. The third set flow rate is greater than the second set flow rate. Based on the pressure gradient changes under the third set operating condition, it is determined that the oil tank vent shut-off valve does not have a liquid seal.

9. The method for monitoring leaks in a fuel evaporation system according to claim 8, characterized in that, The step of determining that the oil tank vent shut-off valve does not have a liquid seal based on the pressure change rate under the third set operating condition includes: If the third set operating condition is in effect, the rate of change of oil tank pressure is obtained until the charcoal canister flow rate reaches the third set flow rate. If the pressure change rate meets the set conditions, it is determined that the oil tank vent shut-off valve is not in a liquid seal condition.

10. The method for monitoring leaks in a fuel evaporation system according to claim 1, characterized in that, The determination that there is no charcoal canister solenoid valve malfunction in the fuel evaporation system based on the rate of change of fuel tank pressure under the first set operating condition includes: In response to the completion of the vacuum establishment process, the duration during which the fuel evaporation system is in the first set operating condition is determined to be the first duration. If the rate of increase of the fuel tank pressure within the first time period is greater than the first rate of increase threshold, it is determined that there is no stuck open fault in the charcoal canister solenoid valve in the fuel evaporation system.

11. The method for monitoring leaks in a fuel evaporation system according to claim 1, characterized in that, The process of replenishing air in the fuel tank includes: Once the fuel evaporation system has been in the second set operating condition for a certain period of time, the fuel tank replenishment process is completed.

12. The method for monitoring leaks in a fuel evaporation system according to claim 1, characterized in that, The process of replenishing air in the fuel tank in response to the fuel tank pressure change under the first set operating condition, determining that there is no charcoal canister solenoid valve malfunction in the fuel evaporation system, includes: In response to the completion of the air replenishment process in the fuel tank, the duration during which the fuel evaporation system is in the first set operating condition is determined to be the first duration. If the change in fuel tank pressure within the first time period is greater than the second minimum fuel tank pressure threshold, it is determined that there is no stuck open fault in the charcoal canister solenoid valve in the fuel evaporation system.

13. The method for monitoring leaks in a fuel evaporation system according to claim 1, characterized in that, The determination that there is no type II leakage in the fuel evaporation system based on the recorded rate of change of fuel tank pressure includes: If the rate of increase of the fuel tank pressure within the first recorded time period is less than the second rate of increase threshold, it is determined that there is no second type of leakage in the fuel evaporation system.

14. The method for monitoring leaks in a fuel evaporation system according to claim 1, characterized in that, The rate of change of oil tank pressure is obtained in the following way: Acquire fuel tank pressure sampling data within the first time period; Based on the oil tank pressure sampling data, the pressure change within a first time period is determined, including the pressure change rate. If the pressure change meets the set conditions, the rate of increase of the tank pressure is determined based on the exponentially weighted moving average of the rate of pressure change within the first time period.

15. The method for monitoring leaks in a fuel evaporation system according to claim 1, characterized in that, The process of detecting the degree of shaking includes: Based on the set indicators, the degree of sway of the vehicle as a whole along the corresponding direction is determined, and the corresponding direction includes the direction perpendicular to the chassis, the direction of travel, and the lateral direction of travel. The maximum value of the vehicle's sway in each corresponding direction is determined as the sway level of the fuel tank.

16. The method for monitoring leaks in a fuel evaporation system according to any one of claims 1 to 9, characterized in that, After determining that there is no charcoal canister solenoid valve malfunction or second-type leakage in the fuel evaporation system based on the rate and amount of fuel tank pressure change during the setting process, the process further includes: Adjust both the charcoal canister ventilation valve and the charcoal canister solenoid valve to the open position to end the leak monitoring process.

17. The method for monitoring leaks in a fuel evaporation system according to any one of claims 1 to 9, characterized in that, The method further includes: If the monitoring conditions or vehicle status conditions are not met, or the charcoal canister ventilation valve or charcoal canister solenoid valve is not in normal working condition, stop the subsequent steps and end the leak monitoring process.

18. A fuel evaporation system leakage monitoring device, characterized in that, include: The condition judgment module is used to determine that the charcoal canister ventilation valve and charcoal canister solenoid valve are in normal working condition in response to the satisfaction of the set monitoring conditions and vehicle status conditions, and to determine that the fuel tank has passed the first shaking degree detection. The first monitoring module is used to determine whether there is a liquid seal or a first type of leakage in the oil tank vent valve based on the process of establishing a vacuum in the oil tank. The first type of leakage is used to indicate the leakage situation corresponding to the leakage point with an equivalent diameter in a first numerical range. The second monitoring module is used to determine, based on the rate and amount of change of fuel tank pressure during the set process, that there is no charcoal canister solenoid valve malfunction or second type of leakage in the fuel evaporation system. The second type of leakage is used to indicate the leakage situation corresponding to the leakage point with an equivalent diameter in the second numerical range. The second monitoring module is specifically used for: Based on the rate of change of fuel tank pressure under the first set operating condition, it is determined that there is no charcoal canister solenoid valve malfunction in the fuel evaporation system. Record the rate of change of the oil tank pressure and determine the extent of the second shaking test of the oil tank; In response to the completion of the air replenishment process in the fuel tank, based on the change in fuel tank pressure under the first set operating condition, it is determined that there is no charcoal canister solenoid valve malfunction in the fuel evaporation system. The completion of the air replenishment process in the fuel tank is used to represent the process of raising the pressure in the fuel tank within a set time period. Based on the recorded rate of change of fuel tank pressure, it is determined that there is no type II leakage in the fuel evaporation system.

19. A control device, characterized in that, include: At least one processor; and a memory communicatively connected to the at least one processor; The memory stores instructions that can be executed by the at least one processor, which, when executed by the at least one processor, cause the control device to perform the fuel vapor system leak monitoring method as described in any one of claims 1 to 17.

20. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the fuel evaporation system leak monitoring method as described in any one of claims 1 to 17.

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