Oil tank venting stop valve liquid seal monitoring method, device, equipment and storage medium

Abstract

This disclosure provides a method, apparatus, device, and storage medium for monitoring the liquid seal of a fuel tank vent valve. The method includes: in response to the fuel evaporation system being in a leak detection vacuum state, acquiring the pressure gradient change detected by a pressure sensor in the fuel evaporation system until the fuel evaporation system ends the leak detection vacuum state; if the pressure gradient change meets set conditions, determining that a liquid seal exists in the fuel tank vent valve. This disclosure achieves simultaneous detection of a liquid seal in the fuel tank vent valve during the leak detection stage of the fuel evaporation system, thereby ensuring that leak detection of the fuel evaporation system is not affected by changes in internal space, effectively avoiding misjudgments of leak faults, and ensuring the accuracy of leak diagnosis when the vehicle is driving on an inclined road.

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 the liquid seal of a fuel tank vent shut-off valve. 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 (which contains a 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 for combustion along with the intake airflow, 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 to reduce the pressure inside the fuel tank to a negative pressure, and then identifying the leak based on the pressure changes throughout the fuel evaporation system.

[0004] However, if the vehicle is on an incline such as a slope, the fuel tank level may be tilted, which may cause the vent valve (the valve at the opening of the pipeline connecting the fuel tank to the charcoal canister) inside the fuel tank to be submerged by fuel (i.e., liquid seal). This will cause the fuel evaporation system to be divided into two parts: the fuel tank and the pipeline. This will significantly reduce the space within the fuel evaporation system for identifying pressure changes, leading to inaccurate leak detection. Summary of the Invention

[0005] This disclosure provides a method, apparatus, equipment, and storage medium for monitoring the liquid seal of an oil tank vent shut-off valve, in order to identify the liquid seal status of the oil tank vent shut-off valve and improve the accuracy of leakage identification.

[0006] In a first aspect, this disclosure provides a method for monitoring the liquid seal of a fuel tank vent shut-off valve, the method comprising:

[0007] In response to the fuel evaporation system being in a leak detection vacuum state, the pressure gradient change detected by the pressure sensor in the fuel evaporation system is acquired until the fuel evaporation system ends the leak detection vacuum state. The fuel evaporation system includes a fuel tank and a charcoal canister connected to each other by pipes, and the pressure sensor is located inside the fuel tank.

[0008] If the pressure gradient change meets the set conditions, it is determined that the oil tank vent shut-off valve is in a liquid seal condition.

[0009] Optionally, the fuel evaporation system includes a charcoal canister vent valve on the charcoal canister and a charcoal canister solenoid valve connected to the charcoal canister outlet, with the two ends of the solenoid valve connected to the charcoal canister and the engine intake manifold, respectively. The fuel evaporation system is in a leak detection and vacuuming state, including: the charcoal canister vent valve is in a closed state and the charcoal canister solenoid valve is in an open state; the fuel evaporation system is out of the leak detection and vacuuming state, including: the charcoal canister vent valve is in a closed state and the charcoal canister solenoid valve is in a closed state.

[0010] Optionally, in response to the fuel evaporation system being in a leak detection vacuum state, the pressure gradient change detected by the pressure sensor in the fuel evaporation system is acquired until the fuel evaporation system ends the leak detection vacuum state, including: in response to the fuel evaporation system being in a leak detection vacuum state, acquiring the pressure drop gradient for each set unit of time until the fuel evaporation system ends the leak detection vacuum state; and determining the pressure gradient change based on the pressure drop gradient for each set unit of time.

[0011] Optionally, based on the pressure drop gradient for each set unit time, the pressure gradient change is determined, including: determining that the pressure gradient change meets the set conditions when at least one of the following conditions is met: the maximum value of the pressure drop gradient for the set unit time is greater than a first set value; the absolute value of the difference between the maximum value and the median value of the pressure drop gradient for the set unit time is taken as the first absolute value, which is greater than a second set value; the absolute value of the difference between the minimum value and the median value of the pressure drop gradient for the set unit time is taken as the second absolute value, which is greater than a third set value; the variance of the pressure drop gradient for the set unit time is taken, which is greater than a fourth set value.

[0012] Optionally, the set conditions include at least one of the following: a sudden change occurs during the decrease of tank pressure; the rate of decrease of tank pressure is greater than the set rate.

[0013] Optionally, in response to the fuel evaporation system being in a leak detection state, the pressure gradient change detected by the pressure sensor in the fuel evaporation system is acquired, and after the fuel evaporation system ends the leak detection and vacuuming state, the method further includes: if the pressure gradient change does not meet the set conditions, determining that the fuel tank vent shut-off valve does not have a liquid seal; and based on the leak detection results of the fuel evaporation system, determining whether there is a leak in the fuel evaporation system.

[0014] Optionally, if the pressure gradient change meets the set conditions, after determining that there is a liquid seal in the fuel tank vent valve, the process further includes: ending the leak detection of the fuel evaporation system and determining that the detection result is unusable.

[0015] Secondly, this disclosure provides a liquid seal monitoring device for a fuel tank vent shut-off valve, the fuel tank vent shut-off valve liquid seal monitoring device comprising:

[0016] The acquisition module is used to acquire the pressure gradient change detected by the pressure sensor in the fuel evaporation system in response to the fuel evaporation system being in a leak detection vacuum state, until the fuel evaporation system ends the leak detection vacuum state. The fuel evaporation system includes a fuel tank and a charcoal canister connected to each other by pipes, and the pressure sensor is located in the fuel tank.

[0017] The determination module is used to determine whether the oil tank vent shut-off valve has a liquid seal if the pressure gradient change meets the set conditions.

[0018] Optionally, the acquisition module specifically includes a fuel evaporation system comprising a charcoal canister vent valve on the charcoal canister and a charcoal canister solenoid valve connected to the charcoal canister outlet. The two ends of the charcoal canister solenoid valve are respectively connected to the charcoal canister and the engine intake manifold. When the fuel evaporation system is in a leak detection vacuum state, the charcoal canister vent valve is in a closed state and the charcoal canister solenoid valve is in an open state. When the fuel evaporation system ends the leak detection vacuum state, the charcoal canister vent valve is in a closed state and the charcoal canister solenoid valve is in a closed state.

[0019] Optionally, the acquisition module is specifically used to acquire the pressure drop gradient for each set unit of time in response to the fuel evaporation system being in a leak detection vacuum state, until the fuel evaporation system ends the leak detection vacuum state; and to determine the pressure gradient change based on the pressure drop gradient for each set unit of time.

[0020] Optionally, the acquisition module is specifically used to determine that the pressure gradient change meets the set conditions when at least one of the following conditions is met: the maximum value of the pressure drop gradient over a set unit time is greater than a first set value; the absolute value of the difference between the maximum value and the median value of the pressure drop gradient over a set unit time is taken as the first absolute value, which is greater than a second set value; the absolute value of the difference between the minimum value and the median value of the pressure drop gradient over a set unit time is taken as the second absolute value, which is greater than a third set value; and the variance of the pressure drop gradient over a set unit time is taken, which is greater than a fourth set value.

[0021] Optionally, the determining module is specifically used to set conditions, including at least one of the following: a sudden change occurred during the oil tank pressure drop; the oil tank pressure drop rate is greater than the set rate.

[0022] Optionally, the determining module is further configured to, in response to the fuel evaporation system being in a leak detection vacuum state, acquire the pressure gradient change detected by the pressure sensor in the fuel evaporation system, and if the pressure gradient change does not meet the set conditions after the fuel evaporation system ends the leak detection vacuum state, determine that the fuel tank vent shut-off valve does not have a liquid seal; and determine whether there is a leak in the fuel evaporation system based on the leak detection results of the fuel evaporation system.

[0023] Optionally, the determination module is also used to, if the pressure gradient change meets the set conditions, determine that there is a liquid seal in the fuel tank vent valve, end the leak detection of the fuel evaporation system, and determine that the detection result is unusable.

[0024] Thirdly, this disclosure also provides a control device, which includes:

[0025] At least one processor;

[0026] and memory that is communicatively connected to at least one processor;

[0027] The memory stores instructions that can be executed by at least one processor, which, when executed by at least one processor, cause the control device to perform the oil tank vent shut-off valve liquid seal monitoring method corresponding to any embodiment of the first aspect of this disclosure.

[0028] Fourthly, this disclosure also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the oil tank vent shut-off valve liquid seal monitoring method as described in any of the first aspects of this disclosure.

[0029] Fifthly, this disclosure also provides a computer program product comprising computer-executable instructions, which, when executed by a processor, are used to implement the oil tank vent shut-off valve liquid seal monitoring method as described in any of the first aspects of this disclosure.

[0030] The fuel tank vent valve liquid seal monitoring method, apparatus, equipment, and storage medium disclosed herein, respond to the fuel evaporation system being in a leak detection vacuum state, acquires the pressure gradient changes detected by the pressure sensor in the fuel evaporation system, and continues until the fuel evaporation system ends the leak detection vacuum state. When the pressure gradient change meets set conditions, it determines that a liquid seal exists in the fuel tank vent valve. Therefore, it is possible to detect the presence of a liquid seal in the fuel tank vent valve simultaneously during the fuel evaporation system leak detection phase, thereby ensuring that the leak detection of the fuel evaporation system is not affected by changes in internal space, effectively avoiding false leak diagnoses, and ensuring the accuracy of leak diagnosis when the vehicle is traveling on an inclined road. Attached Figure Description

[0031] 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.

[0032] Figure 1 This is an application scenario diagram of the oil tank vent shut-off valve liquid seal monitoring method provided in the embodiments of this disclosure;

[0033] Figure 2 A flowchart illustrating a method for monitoring the liquid seal of a fuel tank vent shut-off valve according to an embodiment of this disclosure;

[0034] Figure 3 A flowchart of a method for monitoring the liquid seal of a fuel tank vent shut-off valve, provided in yet another embodiment of this disclosure;

[0035] Figure 4 A schematic diagram of the structure of a liquid seal monitoring device for a fuel tank vent shut-off valve provided in yet another embodiment of this disclosure;

[0036] Figure 5 This is a schematic diagram of the structure of a control device provided in yet another embodiment of this disclosure.

[0037] 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

[0038] 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.

[0039] The following is a description of the terminology used in this disclosure:

[0040] 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 ventilation between the charcoal canister and the engine.

[0041] 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.

[0042] 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.

[0043] Vehicles equipped with gasoline engines experience significant fuel vapor buildup in their fuel evaporation systems due to the volatility of gasoline. To prevent fuel vapor leakage, real-time monitoring of this system is crucial for timely repairs. Current methods for detecting fuel vapor leaks primarily rely on the engine intake manifold vacuum method, which determines the leakage rate based on the rate of air pressure change within the fuel evaporation system during the monitoring period. However, since pressure is closely related to space, when a vehicle is on an incline, such as a ramp, causing the fuel tank level to tilt, the vent valve (the valve at the opening of the pipe connecting the fuel tank to the charcoal canister) may be submerged in fuel (i.e., liquid-sealed). In this situation, the fuel evaporation system is divided into two parts: the fuel tank and the pipes (there is still space within the fuel tank, but the connection between the fuel tank and the charcoal canister is liquid-sealed, while there is also some space within the charcoal canister and the pipes, preventing communication between the two spaces). This significantly alters the space adjacent to the pressure sensor within the fuel evaporation system (usually located between the fuel tank and the charcoal canister or inside the fuel tank), drastically reducing the space available for pressure change detection and leading to inaccurate leak detection.

[0044] To address the aforementioned issues, this disclosure provides a method for monitoring the liquid seal of a fuel tank vent valve. By detecting changes in the pressure gradient within the fuel tank during the fuel evaporation system leakage detection phase, the method determines whether a liquid seal exists in the fuel tank vent valve, thereby improving the accuracy of leak identification.

[0045] The application scenarios of the embodiments of this disclosure are explained below:

[0046] Figure 1 This diagram illustrates an application scenario of the oil tank vent shut-off valve liquid seal monitoring method provided in this embodiment of the 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 detection 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 detected pressure change.

[0047] It should be noted that, Figure 1 The scenario shown uses only one pressure sensor as an example, but this disclosure is not limited to this; that is, the number of pressure sensors can be arbitrary.

[0048] The following detailed description of the oil tank vent shut-off valve liquid seal 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.

[0049] Figure 2 This is a flowchart illustrating a method for monitoring the liquid seal of a fuel tank vent shut-off valve, as provided in one embodiment of this disclosure. Figure 2 As shown, it includes the following steps:

[0050] Step S201: In response to the fuel evaporation system being in a leak detection vacuum state, acquire the pressure gradient change detected by the pressure sensor in the fuel evaporation system until the fuel evaporation system ends the leak detection vacuum state.

[0051] The fuel evaporation system includes a fuel tank and a charcoal canister that are interconnected by pipes, and the pressure sensor is located inside the fuel tank.

[0052] Specifically, leak detection of the fuel evaporation system is generally carried out while the car is in motion or the engine is running. At this time, the engine can work to draw in oil vapor from the fuel evaporation system through the engine intake manifold, and then the leak can be detected by the engine intake manifold vacuum method.

[0053] Leak detection, before vacuuming, may also include checking whether the charcoal canister solenoid valve and charcoal canister vent valve are functioning properly. This ensures that the fuel evaporation system can operate normally during vacuuming, thereby guaranteeing the reliability of the detection results.

[0054] The fuel evaporation system is in a leak detection and vacuuming state. This can also be achieved when the processor or server receives a signal that the charcoal canister solenoid valve is open and the charcoal canister vent valve is closed. At this time, the pressure sensor will detect changes in the pressure gradient (or it can receive a signal from the pressure sensor that the pressure has started to drop, indicating that vacuuming has begun).

[0055] The fuel evaporation system ends the leak detection and vacuuming state, that is, the processor or server receives a signal that the charcoal canister solenoid valve is closed (at this time the charcoal canister vent valve is still closed).

[0056] From the moment the fuel evaporation system enters the leak detection vacuuming state until it exits, the air pressure inside the fuel evaporation system continuously decreases due to the engine intake manifold evacuating the system. If there is a leak in the fuel evaporation system at this time, the change in air pressure will differ from the change in air pressure when there is no leak. Therefore, it is possible to determine whether there is a leak in the fuel evaporation system.

[0057] At this point, the judgment of air pressure changes is based on its overall trend, such as the average rate of descent. However, if the vehicle is on an inclined road, causing the gasoline in the fuel tank to liquid seal the vent valve under the influence of gravity, the space in contact with the pressure sensor will instantly shrink, and the air pressure change will also show an instantaneous change or an excessively rapid rate of descent. Therefore, the presence of a liquid seal can be determined based on the instantaneous changes in air pressure or the overall rate of change, i.e., the change in pressure gradient.

[0058] Step S202: If the pressure gradient change meets the set conditions, determine that the oil tank vent shut-off valve has a liquid seal.

[0059] Specifically, since the pressure gradient change can be represented by different indicators, such as the extreme value and variance of the pressure drop gradient, there are also different setting conditions to determine whether a liquid seal exists.

[0060] The set conditions are used to indicate that the instantaneous change of the pressure drop gradient exceeds the set standard. At this time, it can be determined that it is caused by the instantaneous change of the space connected to the pressure sensor, so it can be directly determined that there is a liquid seal. Alternatively, if the pressure drop rate exceeds the set rate, it can be determined that it is caused by the space connected to the pressure sensor being too small. The only reason that the space is too small is usually liquid seal, so it can also be determined that there is a liquid seal.

[0061] The fuel tank vent valve liquid seal monitoring method provided in this embodiment acquires the pressure gradient changes detected by the pressure sensor in the fuel evaporation system in response to the fuel evaporation system being in a leak detection vacuum state. This continues until the fuel evaporation system ends the leak detection vacuum state, and when the pressure gradient change meets set conditions, it determines that a liquid seal exists in the fuel tank vent valve. Therefore, it is possible to detect the presence of a liquid seal in the fuel tank vent valve simultaneously during the fuel evaporation system leak detection phase, ensuring that leak detection in the fuel evaporation system is not affected by changes in internal space, effectively avoiding false leak diagnoses, and guaranteeing the accuracy of leak diagnosis when the vehicle is driving on an inclined road.

[0062] Figure 3 This is a flowchart illustrating a method for monitoring the liquid seal of a fuel tank vent shut-off valve, as provided in this disclosure. Figure 3 As shown, the method for monitoring the liquid seal of the oil tank vent shut-off valve provided in this embodiment includes the following steps:

[0063] Step S301: In response to the fuel evaporation system being in a leak detection vacuum state, obtain the pressure drop gradient for each set unit of time until the fuel evaporation system ends the leak detection vacuum state.

[0064] Specifically, when the fuel evaporation system enters the vacuuming stage for leak detection, the pressure sensor collects the air pressure in the fuel tank every set unit time interval (which can be any unit time interval, such as 50ms, 100ms, 150ms, etc.). The difference between two adjacent air pressure measurements is used to obtain the pressure drop gradient value of the fuel tank within the set unit time interval.

[0065] Furthermore, considering that the fuel evaporation system includes a charcoal canister vent valve and a charcoal canister solenoid valve connected to the charcoal canister outlet, the fuel evaporation system can be in a leak detection and vacuum state.

[0066] The conclusion of the fuel evaporation system leak detection vacuum state can be determined by detecting that the charcoal canister vent valve is closed and the charcoal canister solenoid valve is open. (The conclusion of the conclusion of the leak detection vacuum state is determined after the fuel evaporation system has entered the leak detection vacuum state.)

[0067] Step S302: Determine the pressure gradient change based on the pressure drop gradient for each set unit of time.

[0068] Condition.

[0069] Specifically, the pressure gradient change is determined by several pressure drop gradient values ​​detected during the leak detection phase (from the start of the leak detection vacuuming state to the end of the leak detection vacuuming state).

[0070] The number of pressure drop gradient values ​​can be determined by the ratio of the time the fuel evaporation system is in the 5th stage of leak detection to the set unit duration.

[0071] Furthermore, it is necessary to combine the pressure gradient changes with the set conditions to determine whether a liquid seal exists. The set conditions may include at least one of the following:

[0072] A sudden change occurred during the pressure drop in the fuel tank;

[0073] The pressure drop rate is greater than the set rate.

[0074] 0. Specifically, the physical meaning of the set conditions can be an instantaneous change in the tank pressure from the perspective of the pressure sensor (generally a sudden and significant drop), a sudden change in the space inside the tank that is directly connected to the pressure sensor (generally a sudden reduction), or the pressure drop rate inside the tank is too fast, or the space that is the same as the pressure sensor is too small (which leads to the pressure drop rate being greater than the set rate).

[0075] The following sections, in conjunction with steps S303 to S306, provide specific explanations for different scenarios.

[0076] 5. Step S303: When the maximum value of the pressure drop gradient per unit time is greater than the first set value,

[0077] Determine whether the pressure gradient change meets the set conditions.

[0078] Specifically, the pressure gradient change can be judged by comparing it with the set conditions to see if the set conditions are met. Here, the set conditions represent the conditions that the pressure drop gradient value should meet when a liquid seal is present.

[0079] If the pressure gradient change meets the set conditions, it is considered that a liquid seal exists. However, since the pressure change detected by the pressure sensor is affected by spatial changes, the result cannot accurately determine whether there is a leak in the fuel evaporation system. If the pressure gradient change does not meet the set conditions, it is considered that there is no liquid seal. The detection results obtained in the leak detection stage can be used for further analysis.

[0080] When the pressure gradient change is represented by the maximum value of the pressure drop gradient, the corresponding setting condition can be greater than the first set value. If the pressure drop gradient is greater than the first set value, then a liquid seal is considered to exist.

[0081] Step S304: Take the absolute value of the difference between the maximum value and the median value of the pressure drop gradient over a set unit time period as the first absolute value. When the first absolute value is greater than the second set value, it is determined that the pressure gradient change meets the set conditions.

[0082] Specifically, when the pressure gradient change is represented by the absolute value of the difference between the maximum value and the median value of the pressure drop gradient (i.e., the first absolute value), the corresponding setting condition can be greater than the second setting value. If the first absolute value is greater than the second setting value, then a liquid seal is considered to exist.

[0083] Compared to using the maximum value directly, the first absolute value can better reflect the severity and significance of the mutation.

[0084] Step S305: Take the absolute value of the difference between the minimum and median values ​​of the pressure drop gradient over a set unit time period as the second absolute value. When the second absolute value is greater than the third set value, it is determined that the pressure gradient change meets the set conditions.

[0085] Specifically, when the pressure gradient change is represented by the absolute value of the difference between the minimum and median values ​​of the pressure drop gradient (i.e., the second absolute value), the corresponding setting condition can be greater than the third setting value. If the second absolute value is greater than the third setting value, then a liquid seal is considered to exist.

[0086] Ideally, the pressure gradient should decrease uniformly. If the pressure gradient suddenly decreases or increases at a certain moment, it may be due to a sudden change in the space within the tank. In this case, the first absolute value can be used for judgment. However, if the pressure gradient decreases too rapidly but the process is uniform, the first absolute value cannot be used for judgment. For example, if the collected pressure gradients are 1, 1, 3, 3, 3, the maximum value is 3, the minimum value is 1, and the median is 3. The first absolute value is 0, which obviously cannot determine the presence of a liquid seal. The second absolute value is 2. If the third absolute value is set to 1, then the presence of a liquid seal can be confirmed.

[0087] Step S306: Take the variance of the pressure drop gradient over a set unit time. When the variance is greater than the fourth set value, determine that the pressure gradient change meets the set conditions.

[0088] Specifically, when the pressure gradient change is represented by the variance of the pressure drop gradient, the corresponding setting condition can be greater than the fourth setting value. If the variance is greater than the fourth setting value, then a liquid seal is considered to exist.

[0089] Similar to the first and second absolute values, variance can also measure the fluctuation of pressure gradient changes. When the fluctuation is too drastic, it is usually caused by a sudden change in the pressure drop gradient, so the existence of a liquid seal can be assumed.

[0090] Steps S303 to S306 are parallel optional steps, and those skilled in the art can choose to perform any step according to the actual situation.

[0091] Step S307: End the leak detection of the fuel evaporation system and determine that the detection results are unusable.

[0092] Specifically, if it is determined that the vent valve in the fuel tank is liquid-sealed, the subsequent fuel evaporation system leak detection steps (such as calculations related to the detection results) can be terminated. This is because, due to the presence of the liquid seal, the obtained fuel tank pressure changes are not only affected by the leak, and if conventional judgment methods are used, the conclusions are likely to differ significantly from the actual results. Therefore, in this case, it can be directly determined that the detection results are unusable.

[0093] Step S308: If the pressure gradient change does not meet the set conditions, determine that there is no liquid seal in the oil tank vent shut-off valve.

[0094] Specifically, if the pressure gradient change does not meet the set conditions, it indicates that the vent shut-off valve is not liquid-sealed. Therefore, the data from the vacuuming stage of the leak detection is usable and can be used for subsequent calculations.

[0095] Step S309: Based on the leak detection results of the fuel evaporation system, determine whether there is a leak in the fuel evaporation system.

[0096] Specifically, the method for determining whether a leak exists based on the leak detection results can be directly adopted from the existing engine intake manifold vacuum method. Since the aforementioned steps have confirmed that there is no liquid seal in the fuel tank, it can be assumed that the pressure change during the vacuuming stage of the leak detection is affected by the leak. Therefore, the judgment can be made based on the corresponding leak detection results, and the reliability of the results can be guaranteed.

[0097] Steps S308 to S309 are parallel optional steps to step S307. Those skilled in the art can select the corresponding steps to perform according to the actual situation.

[0098] The fuel tank vent shut-off valve liquid seal monitoring method provided in this embodiment acquires the pressure drop gradient for each set unit of time during the fuel evaporation system leakage detection stage. Based on this pressure drop gradient, it determines the pressure gradient change and selects corresponding set conditions for judgment according to different calculation parameters of the pressure drop gradient. If the set conditions are met, subsequent detection is stopped, and the detection result is directly determined to be unusable. If the set conditions are not met, subsequent detection continues. Therefore, while performing leakage detection, it is possible to accurately determine whether a liquid seal exists in the fuel evaporation system, thereby effectively ensuring that leakage detection is not affected by other factors and improving the accuracy and reliability of the detection results.

[0099] Figure 4 This is a schematic diagram of the structure of a liquid seal monitoring device for an oil tank vent shut-off valve provided in this disclosure. Figure 4 As shown, the oil tank vent shut-off valve liquid seal monitoring device 400 includes: an acquisition module 410 and a determination module 420. Wherein:

[0100] The acquisition module 410 is used to acquire the pressure gradient change detected by the pressure sensor in the fuel evaporation system in response to the fuel evaporation system being in a leak detection vacuum state until the fuel evaporation system ends the leak detection vacuum state. The fuel evaporation system includes a fuel tank and a charcoal canister connected to each other by pipes, and the pressure sensor is located in the fuel tank.

[0101] The determination module 420 is used to determine whether the oil tank vent shut-off valve has a liquid seal if the pressure gradient change meets the set conditions.

[0102] Optionally, the acquisition module 410 specifically includes a fuel evaporation system comprising a charcoal canister vent valve on the charcoal canister and a charcoal canister solenoid valve connected to the charcoal canister outlet. The two ends of the charcoal canister solenoid valve are respectively connected to the charcoal canister and the engine intake manifold. When the fuel evaporation system is in a leak detection vacuum state, the charcoal canister vent valve is in a closed state and the charcoal canister solenoid valve is in an open state. When the fuel evaporation system ends the leak detection vacuum state, the charcoal canister vent valve is in a closed state and the charcoal canister solenoid valve is in a closed state.

[0103] Optionally, the acquisition module 410 is specifically used to acquire the pressure drop gradient for each set unit of time in response to the fuel evaporation system being in a leak detection vacuum state until the fuel evaporation system ends the leak detection vacuum state; and to determine the pressure gradient change based on the pressure drop gradient for each set unit of time.

[0104] Optionally, the acquisition module 410 is specifically used to determine that the pressure gradient change meets the set conditions when at least one of the following conditions is met: the maximum value of the pressure drop gradient over a set unit time is greater than a first set value; the absolute value of the difference between the maximum value and the median value of the pressure drop gradient over a set unit time is taken as the first absolute value, and the first absolute value is greater than a second set value; the absolute value of the difference between the minimum value and the median value of the pressure drop gradient over a set unit time is taken as the second absolute value, and the second absolute value is greater than a third set value; the variance of the pressure drop gradient over a set unit time is taken, and the variance is greater than a fourth set value.

[0105] Optionally, the determining module 420 is specifically used to set conditions, including at least one of the following: a sudden change occurred during the oil tank pressure drop; the oil tank pressure drop rate is greater than the set rate.

[0106] Optionally, the determining module 420 is further configured to, in response to the fuel evaporation system being in a leak detection vacuum state, acquire the pressure gradient change detected by the pressure sensor in the fuel evaporation system, and if the pressure gradient change does not meet the set conditions after the fuel evaporation system ends the leak detection vacuum state, determine that the fuel tank vent shut-off valve does not have a liquid seal; and determine whether there is a leak in the fuel evaporation system based on the leak detection results of the fuel evaporation system.

[0107] Optionally, the determination module 420 is also used to, if the pressure gradient change meets the set conditions, determine that there is a liquid seal in the fuel tank vent valve, end the leak detection of the fuel evaporation system, and determine that the detection result is unusable.

[0108] In this embodiment, the fuel tank vent valve liquid seal monitoring device, through the combination of various modules, can simultaneously detect whether there is a liquid seal in the fuel tank vent valve during the fuel evaporation system leakage detection stage. This ensures that the leakage detection of the fuel evaporation system is not affected by changes in the internal space, and guarantees the accuracy of leakage diagnosis when the vehicle is driving on an inclined road.

[0109] 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.

[0110] 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 oil tank vent shut-off valve liquid seal monitoring method provided in any of the above embodiments.

[0111] The memory 510 and the processor 520 can be connected via a bus 530.

[0112] The relevant explanations can be understood by referring to the corresponding descriptions and effects in the method embodiments, and will not be repeated here.

[0113] 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 3 The corresponding embodiment of the oil tank vent shut-off valve liquid seal monitoring method.

[0114] The computer-readable storage medium can be ROM, random access memory (RAM), CD-ROM, magnetic tape, floppy disk, and optical data storage device, etc.

[0115] 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 3 The corresponding embodiment of the oil tank vent shut-off valve liquid seal monitoring method.

[0116] 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.

[0117] 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.

[0118] 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. An oil tank breather valve liquid seal monitoring method, characterized by, The method includes: In response to the fuel evaporation system being in a leak detection vacuum state, the pressure gradient change detected by the pressure sensor in the fuel evaporation system is acquired until the fuel evaporation system ends the leak detection vacuum state. The fuel evaporation system includes a fuel tank and a charcoal canister connected to each other by pipes, and the pressure sensor is located inside the fuel tank. If the pressure gradient change meets the set conditions, it is determined that the fuel tank vent valve is in a liquid-sealed state; wherein, the liquid-sealed state is used to characterize that when the vehicle is on an inclined road surface, the gasoline in the fuel tank will liquid seal the vent valve under the action of gravity, and in the case of liquid sealing, the space in contact with the pressure sensor will decrease instantaneously; the set conditions include at least one of the following: a sudden change occurs during the fuel tank pressure drop; the fuel tank pressure drop rate is greater than the set rate; The step of responding to the fuel evaporation system being in a vacuum leak detection state, acquiring the pressure gradient change detected by the pressure sensor in the fuel evaporation system, until the fuel evaporation system ends the leak detection vacuum state, includes: In response to the fuel evaporation system being in a vacuum leak detection state, the pressure drop gradient for each set unit of time is acquired until the fuel evaporation system ends the leak detection vacuum state. The pressure gradient change is determined based on the pressure drop gradient for each set unit of time.

2. The oil tank breather valve liquid seal monitoring method according to claim 1, characterized by, The fuel evaporation system includes a charcoal canister vent valve on the charcoal canister and a charcoal canister solenoid valve connected to the charcoal canister outlet. The two ends of the charcoal canister solenoid valve are respectively connected to the charcoal canister and the engine intake manifold. The fuel evaporation system is in a leak detection and vacuum state, including: The charcoal canister ventilation valve is in the closed state, and the charcoal canister solenoid valve is in the open state; The fuel evaporation system has completed its leak detection and vacuuming process, including: The charcoal canister ventilation valve is in the closed state, and the charcoal canister solenoid valve is in the closed state.

3. The oil tank breather valve liquid seal monitoring method according to claim 1, characterized by, The determination of the pressure gradient change based on the pressure drop gradient for each set unit of time includes: The pressure gradient change is determined to meet the set conditions when at least one of the following conditions is met: The maximum value of the pressure drop gradient over a set unit of time is greater than the first set value; The absolute value of the difference between the maximum value and the median value of the pressure drop gradient over the set unit time is taken as the first absolute value, and the first absolute value is greater than the second set value. The absolute value of the difference between the minimum and median values ​​of the pressure drop gradient over the set unit time is taken as the second absolute value, which is greater than the third set value. The variance of the pressure drop gradient over the set unit time is taken, and the variance is greater than a fourth set value.

4. The oil tank breather valve liquid seal monitoring method according to any one of claims 1 to 3, characterized by, The step of responding to the fuel evaporation system being in a leak detection vacuum state, acquiring the pressure gradient change detected by the pressure sensor in the fuel evaporation system, and continuing until the fuel evaporation system ends the leak detection vacuum state, further includes: If the pressure gradient change does not meet the set conditions, it is determined that the oil tank vent shut-off valve is not in a liquid seal condition; Based on the leak detection results of the fuel evaporation system, determine whether there is a leak in the fuel evaporation system.

5. The method for monitoring the liquid seal of the oil tank vent shut-off valve according to any one of claims 1 to 3, characterized in that, If the pressure gradient change meets the set conditions, after determining that the oil tank vent shut-off valve has a liquid seal, the method further includes: The leak detection of the fuel evaporation system was terminated, and the leak detection results were determined to be unusable.

6. A liquid seal monitoring device for a fuel tank vent shut-off valve, characterized in that, include: The acquisition module is used to acquire the pressure gradient change detected by the pressure sensor in the fuel evaporation system in response to the fuel evaporation system being in a leak detection vacuum state, until the fuel evaporation system ends the leak detection vacuum state. The fuel evaporation system includes a fuel tank and a charcoal canister connected to each other by pipes, and the pressure sensor is located in the fuel tank. The determination module is used to determine whether the fuel tank vent valve is in a liquid-sealed state if the pressure gradient change meets the set conditions; wherein, the liquid-sealed state is used to characterize that when the vehicle is on an inclined road surface, the gasoline in the fuel tank will liquid seal the vent valve under the action of gravity, and in the case of liquid sealing, the space in contact with the pressure sensor will decrease instantaneously; the set conditions include at least one of the following: a sudden change occurs during the fuel tank pressure drop; the fuel tank pressure drop rate is greater than the set rate; The acquisition module is specifically used to acquire the pressure drop gradient for each set unit of time in response to the fuel evaporation system being in a vacuum leak detection state, until the fuel evaporation system ends the leak detection vacuum state; and to determine the pressure gradient change based on the pressure drop gradient for each set unit of time.

7. 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 are executed by the at least one processor to cause the control device to perform the oil tank vent shut-off valve liquid seal monitoring method as described in any one of claims 1 to 5.

8. 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 oil tank vent shut-off valve liquid seal monitoring method as described in any one of claims 1 to 5.

Images