An integrated valve, fuel system, control method and vehicle

Abstract

The application relates to the technical field of fuel systems, in particular to an integrated valve, a fuel system, a control method and a vehicle. The control method of the fuel system comprises a fuel leakage diagnosis method, the fuel leakage diagnosis method comprises the following steps: controlling an electromagnetic valve to switch to a third state, so that an oil tank, a carbon canister and the integrated valve jointly form a closed diagnosis cavity; controlling a micro air pump to deliver gas into the closed diagnosis cavity through a second pipeline; acquiring a pressure value of the closed diagnosis cavity in real time, stopping the operation of the micro air pump when the pressure value reaches a preset diagnosis value, and controlling the electromagnetic valve to switch to a second state; comparing a pressure decay rate of the closed diagnosis cavity within a first preset time period with a preset pressure decay threshold value, and diagnosing whether the fuel system has leakage according to a comparison result. Whether the engine is working or not, the closed diagnosis cavity can be automatically built and pressure initialized, the small leakage identification accuracy is effectively improved, and the missed detection and false detection probabilities are reduced.

Description

Technical Field

[0001] This application relates to the field of fuel system technology, and more particularly to an integrated valve, a fuel system, a control method, and a vehicle. Background Technology

[0002] In the field of automotive fuel evaporative emission control technology, fuel system leak diagnosis is a crucial step in determining the sealing performance and operational safety of the fuel system. In existing fuel system leak diagnosis solutions, the leak diagnosis module and the fuel tank isolation valve are often arranged separately, with the diagnosis module relying on multiple independent solenoid valves to control the on / off switching of the fuel path.

[0003] This split multi-valve structure requires the laying of a large number of connecting pipelines, resulting in numerous pipeline connection points. This not only complicates the overall assembly structure but also significantly increases the number of weak points in the system's sealing, making it difficult to construct a standard diagnostic chamber with excellent sealing performance. Furthermore, the pressure sampling inside the diagnostic chamber is easily affected by external environmental disturbances, leading to significant distortion of the collected pressure parameters and ultimately resulting in low detection accuracy for minor leaks in the fuel system. Summary of the Invention

[0004] To solve, or at least partially solve, the aforementioned technical problems, this application provides an integrated valve, a fuel system, a control method, and a vehicle.

[0005] The first aspect of this application provides an integrated valve, including a solenoid valve, a micro air pump, a first pipe, a second pipe, a third pipe, and a fourth pipe, wherein the first pipe and the second pipe are located on one side of the solenoid valve, and the third pipe and the fourth pipe are located on the other side of the solenoid valve. The solenoid valve has switchable first, second, and third states. When the solenoid valve is in the first state, it connects the first and third pipes and disconnects the second and fourth pipes. When the solenoid valve is in the second state, it connects the first and fourth pipes and disconnects the second and third pipes. When the solenoid valve is in the third state, it connects the second and third pipes and disconnects the first and fourth pipes. The miniature air pump is located in the second pipeline and is used to deliver gas into the second pipeline when the solenoid valve is in the third state.

[0006] In some embodiments, the system further includes a pressure balancing valve assembly and a pressure balancing pipeline. The pressure balancing valve assembly includes a first pressure balancing valve and a second pressure balancing valve. The pressure balancing pipeline includes a first balancing pipeline and a second balancing pipeline. The first pressure balancing valve is disposed in the first balancing pipeline, and the second pressure balancing valve is disposed in the second balancing pipeline. The first balancing pipeline and the second balancing pipeline are respectively connected to the third pipeline and the fourth pipeline. When the pressure in the third pipe is greater than the pressure in the fourth pipe, and the pressure difference is greater than the first preset pressure difference value, the first pressure balancing valve unilaterally connects the third pipe, the first balancing pipe, and the fourth pipe; when the pressure in the fourth pipe is greater than the pressure in the third pipe, and the pressure difference is greater than the second preset pressure threshold, the second pressure balancing valve unilaterally connects the fourth pipe, the second balancing pipe, and the third pipe.

[0007] A second aspect of this application provides a fuel system including a fuel tank, a charcoal canister, a first connecting pipe, a pressure sensor, a controller, and an integrated valve as described in any of the preceding claims. The third pipe is connected to the charcoal canister, the fuel tank is connected to the charcoal canister via the first connecting pipe, the pressure sensor is disposed on the first connecting pipe, and the controller is connected to the integrated valve and the pressure sensor respectively, for controlling the integrated valve according to the operating conditions of the fuel system or the pressure detected by the pressure sensor.

[0008] In some embodiments, the operating conditions of the fuel system include pre-diagnostic pump pressure conditions and diagnostic pressure holding conditions. In the pre-diagnosis pump pressure condition, the controller is configured to control the solenoid valve to switch to the third state and control the micro air pump to deliver gas into the second pipeline; During the diagnostic pressure holding condition, the controller is configured to control the solenoid valve to switch to the second state.

[0009] In some embodiments, the operating conditions of the fuel system include a parking / pure electric driving condition. When the fuel system is in the parking / pure electric driving condition, the controller is configured to control the solenoid valve to switch to the second state. And / or, The operating conditions of the fuel system include desorption / refueling conditions. When the fuel system is in the desorption / refueling condition, the controller is configured to control the solenoid valve to switch to a first state.

[0010] In some embodiments, the fuel system further includes a second connecting pipe and a charcoal canister solenoid valve, the second connecting pipe being connected between the charcoal canister and the engine intake manifold, and the charcoal canister solenoid valve being disposed on the second connecting pipe for opening or closing the second connecting pipe. The desorption / refueling conditions include a desorption sub-condition and a refueling sub-condition. When the fuel system is in the desorption sub-condition, the controller is configured to control the charcoal canister solenoid valve to open to connect the second connecting pipe. When the fuel system is in the refueling sub-condition, the controller is configured to control the charcoal canister solenoid valve to close to shut off the second connecting pipe.

[0011] A third aspect of this application provides a control method for a fuel system as described in any of the preceding claims, the control method for the fuel system including a fuel leak diagnosis method, the fuel leak diagnosis method including: The solenoid valve is switched to the third state, so that the oil tank, the charcoal canister, and the integrated valve together form a sealed diagnostic chamber; The micro air pump is controlled to deliver gas into the sealed diagnostic chamber through the second pipe; The pressure value of the sealed diagnostic chamber is acquired in real time. When the pressure value reaches the preset diagnostic value, the micro air pump is stopped and the solenoid valve is switched to the second state. The pressure decay rate of the sealed diagnostic chamber within a first preset time period is compared with the preset pressure decay threshold, and the presence of a leak in the fuel system is diagnosed based on the comparison result.

[0012] In some embodiments, the fuel leak diagnosis method further includes: confirming whether the current operating conditions meet the diagnostic conditions, and when the diagnostic conditions are met, controlling the solenoid valve to switch to a third state; The diagnostic conditions include: a single parking time is greater than a second preset time or the cumulative parking time since the last diagnosis is greater than a third preset time, the battery voltage is within a preset voltage range, the fuel level in the fuel tank is within a preset level range, the ambient temperature is within a third preset temperature range, and there is no refueling operation in the fuel tank.

[0013] In some embodiments, the fuel leak diagnosis method further includes acquiring the ambient temperature of the fuel system and setting a corresponding preset pressure decay threshold based on the acquired ambient temperature.

[0014] In some embodiments, when the ambient temperature is within a first preset temperature range, the preset pressure attenuation threshold is used as the preset pressure attenuation value; when the ambient temperature is within a second preset temperature range, the preset pressure attenuation threshold is used as the preset pressure attenuation value; the second preset temperature range is higher than the first preset temperature range; and the second preset pressure attenuation threshold is less than the first preset pressure attenuation threshold.

[0015] In some embodiments, the fuel system control method further includes a fuel system pressure balance control method, the fuel system pressure balance control method comprising: When the fuel system is in a parking / pure electric driving condition, the solenoid valve is switched to the second state, and the micro air pump is turned off.

[0016] In some embodiments, the fuel system control method further includes a fuel system depressurization control method, the fuel system depressurization control method comprising: When the fuel system is in desorption / refueling mode, the solenoid valve is switched to the first state, and the micro air pump is turned off.

[0017] A fourth aspect of this application provides a vehicle including a fuel system as described in any of the preceding claims.

[0018] The technical solution provided in this application has the following advantages compared with the prior art: This integrated valve combines multi-channel on / off control and a miniature air pump into one unit, eliminating the need for multiple separate solenoid valves as in traditional solutions. This significantly reduces pipe joints and sealing points, lowering assembly complexity and reducing the risk of leakage. The three-position solenoid valve precisely switches the on / off of the three air paths. Combined with the miniature air pump integrated into the second pipeline, a sealed diagnostic chamber can be quickly constructed. The chamber's airtightness is significantly improved, preventing external environmental interference with the internal pressure and increasing the accuracy of pressure sampling data. This is beneficial for improving the detection accuracy of minor leaks in the fuel system.

[0019] After the fuel system is equipped with the aforementioned integrated valve, relying on the structural advantages of the integrated valve with fewer joints and high sealing performance, the fuel tank, charcoal canister and integrated valve can quickly form a sealed diagnostic chamber, effectively avoiding the sealing defects caused by too many joints in the traditional multi-valve separate structure; the pressure value in the chamber collected by the pressure sensor is real and reliable, and the controller completes the leakage judgment based on the accurate pressure signal, optimizes the overall leakage diagnosis stability and improves the accuracy of fuel evaporation leakage detection in the whole vehicle.

[0020] This diagnostic method abandons the traditional passive diagnostic mode that relies on engine negative pressure to create a diagnostic environment. Instead, it uses a dedicated pre-diagnostic pumping condition to actively pump pressure into a sealed diagnostic chamber composed of the fuel tank, charcoal canister, and integrated valve, proactively establishing a stable high-pressure diagnostic environment without relying on engine operation. Regardless of whether the engine is running, it can autonomously complete the construction and pressure initialization of the sealed diagnostic chamber, effectively improving the accuracy of identifying minute leaks and reducing the probability of missed or false detections. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1This is a schematic diagram of the integrated valve described in the embodiment of this application when the solenoid valve is in the first state; Figure 2 This is a schematic diagram of the integrated valve described in the embodiment of this application when the solenoid valve is in the second state; Figure 3 This is a schematic diagram of the integrated valve described in the embodiment of this application when the solenoid valve is in the third state; Figure 4 This is a state diagram of the fuel system described in the embodiments of this application when it is necessary to add air to the fuel tank; Figure 5 This is a state diagram of the fuel system described in the embodiments of this application under desorbent conditions; Figure 6 This is a state diagram of the fuel system described in the embodiments of this application under pre-diagnosis pump pressure conditions; Figure 7 This is a state diagram of the fuel system described in the embodiments of this application during the diagnostic pressure-holding condition; Figure 8 This is a flowchart of the fuel leak diagnosis method described in the embodiments of this application.

[0024] Among them, 1. Solenoid valve; 2. Pressure balancing valve assembly; 21. First pressure balancing valve; 22. Second pressure balancing valve; 3. Pressure balancing pipeline; 31. First balancing pipeline; 32. Second balancing pipeline; 4. First pipeline; 5. Second pipeline; 6. Third pipeline; 7. Fourth pipeline; 8. Miniature air pump; 9. Third connecting pipeline; 100. Fuel tank; 101. Filling hose; 102. Circulation hose; 103. Fuel tank cap; 200. First connecting pipe; 300. Pressure sensor; 400. Charcoal canister; 500. Second connecting pipe; 600. Carbon canister solenoid valve; 700, Integrated Valve; 800, Ash Filter; 900, Controller. Detailed Implementation

[0025] To better understand the above-mentioned objectives, features, and advantages of this application, the solution of this application will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0026] Many specific details are set forth in the following description in order to provide a full understanding of this application, but this application may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of this application, and not all embodiments.

[0027] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Please see Figures 1 to 3 This application provides an integrated valve, which includes a solenoid valve 1, a first pipe 4, a second pipe 5, a third pipe 6 and a fourth pipe 7. The solenoid valve 1 is a three-position four-way valve. The first pipe 4 and the second pipe 5 are located on one side of the solenoid valve 1, and the third pipe 6 and the fourth pipe 7 are located on the other side of the solenoid valve 1.

[0029] Solenoid valve 1 has switchable first, second and third states. When solenoid valve 1 is in the first state, it opens the first pipe 4 and the third pipe 6 and closes the second pipe 5 and the fourth pipe 7. When solenoid valve 1 is in the second state, it opens the first pipe 4 and the fourth pipe 7 and closes the second pipe 5 and the third pipe 6. When solenoid valve 1 is in the third state, it opens the second pipe 5 and the third pipe 6 and closes the first pipe 4 and the fourth pipe 7.

[0030] Figure 1 This is a schematic diagram of the integrated valve in an embodiment of the present application when the solenoid valve 1 is in the first state. In the first state, the valve core of the solenoid valve 1 moves to the right position. Figure 2 This is a schematic diagram of the integrated valve in an embodiment of this application when the solenoid valve 1 is in the second state. In the second state, the valve core of the solenoid valve 1 moves to the neutral position. Figure 3 This is a schematic diagram of the integrated valve in an embodiment of this application when the solenoid valve 1 is in the third state. In the third state, the valve core of the solenoid valve 1 moves to the left position.

[0031] A miniature air pump 8 is located in the second pipe 5 and is used to deliver gas into the second pipe 5 when the solenoid valve 1 is in the third state.

[0032] The solenoid valve 1 is the core switching element used to control the opening and closing of fluid passages. Specifically, it can be a step-type solenoid valve or another three-position four-way directional valve with three fixed working positions. In the embodiments of this application, the solenoid valve 1 changes the internal flow channel connectivity by axial movement of the valve core, thereby achieving passage switching for various operating conditions (such as desorption, refueling and depressurization, pump pressure diagnosis, and pressure holding diagnosis) without increasing the number of additional valves. The valve core of the solenoid valve 1 has three positions: left, middle, and right. Each position has four interfaces: a first interface, a second interface, a third interface, and a fourth interface. The first pipe 4 is connected to the first interface, the second pipe 5 is connected to the second interface, the third pipe 6 is connected to the third interface, and the fourth pipe 7 is connected to the fourth interface. When the solenoid valve 1 is switched to the first state, the valve core moves to the right position, the first and third interfaces are internally connected, and the second and fourth interfaces are internally closed. At this time, the first pipe 4 is connected to the third pipe 6, while the second pipe 5 and the fourth pipe 7 are not connected. When solenoid valve 1 switches to the second state, the valve core moves to the neutral position, the first and fourth interfaces are internally connected, and the second and third interfaces are internally cut off. At this time, the first pipe 4 and the fourth pipe 7 are connected, while the second pipe 5 and the third pipe 6 are not connected. When solenoid valve 1 switches to the third state, the valve core moves to the left position, the second and third interfaces are internally connected, and the first and fourth interfaces are internally cut off. At this time, the second pipe 5 and the third pipe 6 are connected, while the first pipe 4 and the fourth pipe 7 are not connected. Solenoid valve 1, through three different connection combinations—namely, the first pipe 4 and the third pipe 6 are connected, the first pipe 4 and the fourth pipe 7 are connected, or the second pipe 5 and the third pipe 6 are connected—corresponds to different system operating states, ensuring that non-working channels are reliably cut off in each state to maintain the airtightness of the diagnostic cavity. The specific driving method, response time, and temperature range of solenoid valve 1 can be set according to the actual application scenario, and this application embodiment does not impose any special limitations on them.

[0033] It should be noted that in some embodiments of this application, the solenoid valve 1 can replace the axial stepping solenoid valve with a rotary stepping solenoid valve. Different passages are opened by rotating the valve core, while still maintaining one solenoid valve to complete multi-condition control. The rotary valve core has better sealing performance and higher sealing reliability in the temperature range of -40℃ to 90℃, making it suitable for high-end models with high sealing requirements or regions with strict regulations.

[0034] The first pipe 4, the second pipe 5, the third pipe 6, and the fourth pipe 7 constitute the fluid delivery pipelines that form the external interface of the integrated valve. The specific shape, material, and size of these pipes can be set according to actual conditions; for example, they can be rigid pipes made of nylon or flexible hoses made of rubber or composite materials. The smoothness of their inner walls should meet the fluid resistance requirements of the fuel evaporation emission system. In the layout where the first pipe 4 and the second pipe 5 are connected to one side of the solenoid valve 1, they can be arranged in parallel or at a certain angle to facilitate docking with external components. Similarly, the connection method of the third pipe 6 and the fourth pipe 7 on the other side can also be adaptively adjusted according to the overall vehicle layout space. The connection relationship between these pipes and the solenoid valve 1 constitutes the main channel for fluid transmission, and their sealing performance directly affects the system's working efficiency. Those skilled in the art will understand that the specific routing and length of the aforementioned pipes are not the limiting focus of this application, as long as effective communication between the two ports of the solenoid valve 1 can be achieved.

[0035] The miniature air pump 8 is integrated on the second pipe 5. Its air inlet can be connected to the atmosphere or connected to the dust filter 800, and its air outlet is connected to the second pipe 5, and then connected to the corresponding interface of the solenoid valve 1.

[0036] In some embodiments of this application, the integrated valve further includes a pressure balancing valve assembly 2 and a pressure balancing pipeline 3. The pressure balancing pipeline 3 is connected between the third pipeline 6 and the fourth pipeline 7. The pressure balancing valve assembly 2 is disposed within the pressure balancing pipeline 3. The pressure balancing valve assembly 2 is configured to open or close the pressure balancing pipeline 3 according to the air pressure difference between the third pipeline 6 and the fourth pipeline 7.

[0037] In practice, one end of the fourth pipe 7 is connected to the solenoid valve 1, and the other end is connected to the interface on the side wall of the third pipe 6 through the balancing pipe 3. The pressure balancing pipe 3 is a bypass channel connecting the third pipe 6 and the fourth pipe 7. The purpose of the pressure balancing pipe 3 is to provide a controlled pressure relief or equalization path when an abnormally high pressure difference occurs between the third pipe 6 and the fourth pipe 7, so as to prevent damage to other structures connected to the integrated valve due to excessive pressure difference.

[0038] The pressure balancing valve assembly 2 is an automatic control component installed within the pressure balancing pipeline 3. Its function is to determine the opening or closing state of the pressure balancing pipeline 3 based on the real-time pressure difference between the third pipeline 6 and the fourth pipeline 7. The pressure balancing valve assembly 2 can be implemented in various ways, such as a combination of spring-loaded check valves or a bidirectional reciprocating pressure-sensitive valve. In one optional embodiment of this application, the pressure balancing valve assembly 2 may include two anti-parallel check valves, used to open when the pressure in the third pipeline 6 is higher than that in the fourth pipeline 7, and to open when the pressure in the fourth pipeline 7 is higher than that in the third pipeline 6, respectively. The specific opening pressure threshold, response speed, and reset characteristics of the pressure balancing valve assembly 2 can be set according to the emission standards and safety requirements of different vehicle models; this embodiment does not impose any special limitations on these aspects.

[0039] Further, in some embodiments of this application, the pressure balancing valve assembly 2 includes a first pressure balancing valve 21 and a second pressure balancing valve 22, and the pressure balancing pipeline 3 includes a first balancing pipeline 31 and a second balancing pipeline 32. The first pressure balancing valve 21 is disposed in the first balancing pipeline 31, and the second pressure balancing valve 22 is disposed in the second balancing pipeline 32. The first balancing pipeline 31 and the second balancing pipeline 32 are respectively connected to the third pipeline 6 and the fourth pipeline 7. When the pressure in the third pipeline 6 is greater than the pressure in the fourth pipeline 7, and the pressure difference is greater than a first preset pressure difference value, the first pressure balancing valve 21 unilaterally opens the third pipeline 6, the first balancing pipeline 31, and the fourth pipeline 7, so that the gas in the third pipeline 6 flows to the fourth pipeline 7 through the first balancing pipeline 31. When the pressure in the fourth pipeline 7 is greater than the pressure in the third pipeline 6, and the pressure difference is greater than a second preset pressure threshold, the second pressure balancing valve 22 unilaterally opens the fourth pipeline 7, the second balancing pipeline 32, and the third pipeline 6, so that the gas in the fourth pipeline 7 flows to the third pipeline 6 through the second balancing pipeline 32.

[0040] Exemplary examples, in some embodiments of this application, the third pipe 6 has a first end interface and a second end interface at both ends, and two first side wall interfaces on its side wall. The fourth pipe 7 has a third end interface and a fourth end interface at both ends, and one second side wall interface on its side wall. The third end interface is connected to the solenoid valve 1, and the fourth end interface is connected to one of the second side wall interfaces through the first balance pipe 31. The first pressure balance valve 21 is disposed within the first balance pipe 31. The first side wall interface is connected to the other second side wall interface through the second balance pipe 32. The second pressure balance valve 22 is disposed within the second balance pipe 32. The first end interface is connected to the solenoid valve, and the second end interface serves as an external interface. When the integrated valve is applied in the fuel system, the second end interface is connected to the charcoal canister.

[0041] The pressure balancing valve assembly 2 is used to prevent system seal failure or component damage due to excessive pressure on one side of the third pipe 6 or the fourth pipe 7, and to prevent gas leakage under unbalanced operating conditions. The pressure balancing valve assembly 2 is connected in conjunction with the third pipe 6, the fourth pipe 7, and the pressure balancing pipe 3. It performs opening or closing actions by sensing the real-time pressure difference between the two third pipes 6 and the fourth pipe 7, thereby achieving bidirectional adaptive pressure balance.

[0042] The first pressure balancing valve 21 is a one-way valve installed in the first balancing pipeline 31. The structure of the first pressure balancing valve 21 can be a spring-loaded check valve, a diaphragm check valve, or a gravity check valve, etc., and this embodiment does not specifically limit this. The installation direction of the first pressure balancing valve 21 in the first balancing pipeline 31 is configured to allow gas to flow only from the third pipeline 6 to the fourth pipeline 7. Its working principle is as follows: when the pressure in the third pipeline 6 is higher than the pressure in the fourth pipeline 7, and the pressure difference between the two exceeds a first preset pressure difference value, the gas pressure overcomes the elastic resistance (such as spring force or diaphragm tension) inside the first pressure balancing valve 21, pushing the valve core to open, thus connecting the third pipeline 6, the first balancing pipeline, and the fourth pipeline 7, allowing high-pressure gas to be released to the low-pressure side through this path; when the pressure difference is less than or equal to the first preset pressure difference value, or when the pressure in the fourth pipeline 7 is higher than that in the third pipeline 6, the first pressure balancing valve 21 remains closed under the action of elastic restoring force. The first preset pressure difference value can be set according to the requirements for pressure balancing accuracy in the actual application scenario.

[0043] The second pressure balancing valve 22 is a one-way valve installed within the second balancing pipeline 32. The structure of the second pressure balancing valve 22 can also be a spring-loaded one-way valve, a diaphragm one-way valve, etc., and its specific material and dimensions can be set according to actual conditions. The installation direction of the second pressure balancing valve 22 in the second balancing pipeline 32 is configured to allow airflow only from the fourth pipeline 7 to the third pipeline 6, that is, opposite to the conduction direction of the first pressure balancing valve 21. Its working principle is as follows: when the pressure in the fourth pipeline 7 is higher than the pressure in the third pipeline 6, and the pressure difference between the two exceeds a second preset pressure threshold, the gas pressure overcomes the internal resistance of the second pressure balancing valve 22, pushing the valve core to open, thus connecting the fourth pipeline 7, the second balancing pipeline, and the third pipeline 6; otherwise, it remains closed.

[0044] Specifically, the working process and principle of the pressure balancing valve assembly 2 in this application are as follows: During the normal operation of the integrated valve, a momentary or continuous pressure difference may occur between the third pipe 6 and the fourth pipe 7 due to the switching action of the solenoid valve 1, the pumping action of the micro air pump 8, or changes in the external ambient temperature. When the pressure on the third pipe 6 side rises abnormally and exceeds the pressure on the fourth pipe 7 side to reach a first preset pressure difference value, the first pressure balancing valve 21 automatically opens, and high-pressure gas flows rapidly to the fourth pipe 7 through the first balancing pipe 31 until the pressure difference between the two sides falls back to a safe range. Subsequently, the first pressure balancing valve 21 automatically closes to prevent reverse gas flow. Similarly, when the pressure on the fourth pipe 7 side rises abnormally and exceeds the pressure on the third pipe 6 side to reach a second preset pressure threshold, the second pressure balancing valve 22 automatically opens, and gas flows to the third pipe 6 through the second balancing pipe 32 to achieve reverse pressure balance. Throughout the process, the first pressure balancing valve 21 and the second pressure balancing valve 22 do not interfere with each other and each independently responds to pressure fluctuations in one direction, ensuring the accuracy and unidirectionality of the pressure balancing action and effectively avoiding the oscillation or accidental opening problems that may occur with bidirectional valves.

[0045] Specifically, when the integrated valve is applied to the fuel system of a vehicle, the integrated valve in this application embodiment achieves universal valve body structure and compatibility with the fuel system requirements of both China VI and China VII emission regulations by replacing the pressure balance valve group 2 with different opening thresholds.

[0046] For example, when using a fuel vehicle that meets the China VI emission standard, the first pressure balancing valve 21 is selected as a one-way valve with an opening pressure of 35 kPa. When the vehicle is in a parking / pure electric driving condition and the solenoid valve 1 is switched to the second state (the first pipeline 4 and the fourth pipeline 7 are connected), when the pressure in the fuel tank 100 rises to 35 kPa, the pressure difference between the third pipeline 6 and the fourth pipeline 7 reaches the opening condition of the first pressure balancing valve 21. The first pressure balancing valve 21 is turned on, and the fuel vapor in the fuel tank 100 is adsorbed by the charcoal canister 400, flows through the internal channels of the third pipeline 6, the first pressure balancing valve 21, the fourth pipeline 7, and the solenoid valve 1, and is then discharged into the atmosphere through the first pipeline 4. After the pressure in the fuel tank 100 drops back to the safe range, the first pressure balancing valve 21 closes, and the system returns to a closed state. When used with fuel vehicles meeting the China VII emission standard, the valve body structure remains unchanged, but the first pressure balancing valve 21 is replaced with a one-way valve with an opening pressure of 45 kPa. Under normal operating conditions, the internal pressure of the fuel tank 100 is always below 45 kPa, the first pressure balancing valve 21 is closed throughout, the third pipe 6 and the fourth pipe 7 are permanently isolated, and the charcoal canister solenoid valve 600 is kept closed synchronously. The fuel tank 100, charcoal canister 400, and integrated valve 700 form a fully enclosed cavity, and all fuel vapor is sealed inside the system, meeting the China VII hybrid closed high-pressure fuel tank 100 regulations. Only when the system abnormally overpressures to more than 45 kPa will the first pressure balancing valve 21 open briefly to release pressure and protect the structural safety of the fuel tank 100.

[0047] Furthermore, the integrated valve body has an integrally formed heat dissipation fin (not shown in the figure) on the outside. The heat dissipation fin and the valve body are injection molded as one piece, which increases the heat dissipation area of ​​the valve body. The ambient air in the vehicle travels along the gaps of the heat dissipation fin to exchange heat, continuously carrying away the heat generated by the built-in micro air pump 8, the compression heat of the valve body cavity, and the high-temperature radiation heat from the environment.

[0048] like Figures 4 to 7 As shown in the illustration, this application also provides a fuel system including a fuel tank 100, a charcoal canister 400, a first connecting pipe 200, a pressure sensor 300, a controller 900, and an integrated valve 700. A third pipe 6 is connected to the charcoal canister 400. The fuel tank 100 is connected to a refueling pipe 101, one end of which communicates with the interior of the fuel tank 100, and the other end is connected to the fuel tank cap 103. The fuel tank 100 is connected to the charcoal canister 400 via the first connecting pipe 200. The pressure sensor 300 is located on the first connecting pipe 200. The first connecting pipe 200 is also connected to the refueling pipe 101 via a circulation pipe 102 to achieve fuel recovery. The controller 900 is connected to the integrated valve 700 and the pressure sensor 300, respectively, and is used to control the integrated valve 700 according to the operating conditions of the fuel system or the pressure detected by the pressure sensor 300.

[0049] The fuel tank 100 is a container used to store vehicle fuel, and its internal space constitutes the main source of fuel vapor generation. The fuel tank 100 is connected to the charcoal canister 400 via a first connecting pipe 200, so that the fuel vapor generated in the fuel tank 100 can be transferred to the charcoal canister 400 for adsorption treatment, or used as a monitoring object for pressure changes under diagnostic conditions.

[0050] The charcoal canister 400 refers to a device filled with adsorbent material (such as activated carbon) for adsorbing and temporarily storing fuel vapor from the fuel tank 100, preventing it from being directly released into the atmosphere. In some embodiments of this application, the charcoal canister 400 serves as an oil-gas separator and temporary storage unit. One connection port of the charcoal canister 400 is connected to the fuel tank 100 via a first connection pipe 200, and the other connection port is connected to the second end interface of the third pipe 6.

[0051] The pressure sensor 300 is an electronic component used to detect the internal pressure value of the fuel system; it can also be referred to as a VPS (Vehicle Pressure Sensor). In the embodiments of this application, the pressure sensor 300 is disposed on the first connecting pipe 200, serving as the core data acquisition component of the diagnostic strategy, and monitors the pressure changes of the fuel tank 100 in real time. The pressure sensor 300 is electrically connected to the controller 900, transmitting the detected analog or digital pressure signal to the controller 900 so that the controller 900 can determine whether there is a leak in the system or control the action of the actuators based on the pressure value. The accuracy, range, and response speed of the pressure sensor 300 can be set according to the diagnostic accuracy requirements; for example, it can be a piezoresistive sensor or a capacitive sensor. This application embodiment does not impose any special limitations on this.

[0052] The controller 900 refers to the vehicle's electronic control unit (ECU), which stores control programs and diagnostic strategy algorithms. In the embodiments of this application, the controller 900 establishes electrical connections with the integrated valve 700 and the pressure sensor 300, forming a closed-loop control system. The controller 900 is the brain of the entire fuel system, dynamically generating and issuing control commands based on the vehicle's operating conditions (such as parking, pure electric driving, engine running, etc.) or the real-time pressure value fed back by the pressure sensor 300. For example, the controller 900 can control the solenoid valve 1 in the integrated valve to switch the valve core position to change the internal flow path, and simultaneously control the opening and closing state of the micro air pump 8, thereby realizing the automatic switching of various working modes such as air replenishment, desorption, pumping pressure, and pressure holding. The controller 900 can also analyze the pressure decay rate according to preset diagnostic logic to determine the system leakage situation.

[0053] The operating conditions of the fuel system include parking / pure electric driving, desorption / refueling, pre-diagnostic pump pressure, and diagnostic pressure holding.

[0054] Among them, the pre-disconnect pump pressure condition refers to the initial stage of the fuel vapor emission leak diagnosis process, which requires establishing a positive pressure environment within the fuel system. For example... Figure 6 As shown, under this operating condition, the controller 900 is configured to switch the solenoid valve 1 to the third state. At this time, the second pipe 5 and the third pipe 6 are connected, while the first pipe 4 and the fourth pipe 7 are disconnected. The controller 900 controls the micro air pump 8 to start, and the generated pressurized gas enters through the second pipe 5, flows through the internal channel of the solenoid valve 1 to the third pipe 6, and is then injected into the sealed diagnostic chamber formed by the fuel tank 100, the charcoal canister 400, and the integrated valve 700. This state disconnects the fuel system from the atmosphere and the engine intake manifold, ensuring that the input gas pressure is fully used to build the initial pressure environment required for diagnostics.

[0055] The pressure maintenance interruption condition refers to the stage after pump pressurization is completed, where pressurization is stopped and the system's pressure maintenance capability is monitored to determine if leakage exists. For example... Figure 7 As shown, under this operating condition, the controller 900 is configured to switch the solenoid valve 1 to the second state, opening the first pipe 4 and the fourth pipe 7, while cutting off the second pipe 5 and the third pipe 6. At this time, the micro air pump 8 stops working, sealing the inlet and outlet channels of the sealed diagnostic chamber (or forming an internal self-circulating closed loop), thus ensuring the fuel system is completely sealed. During this stage, the pressure sensor 300 collects the pressure value inside the fuel tank 100 in real time, and the controller 900 determines the fuel system's sealing performance based on the pressure decay rate per unit time.

[0056] The parking / pure electric driving condition refers to the condition where the vehicle is parked with the engine off or where a hybrid vehicle is driven solely by the battery-powered motor. In this condition, the controller 900 is configured to switch the solenoid valve 1 to the second state. At this time, the valve core of solenoid valve 1 moves to the neutral position, the first pipe 4 and the fourth pipe 7 are connected, and the second pipe 5 and the third pipe 6 are cut off. When the pressure of the fuel vapor in the fuel tank 100 does not reach the first preset pressure threshold, the first pressure balancing valve 21 is closed. The fuel vapor in the fuel tank 100 is discharged to the atmosphere through the integrated valve 700, but instead enters the charcoal canister 400 for adsorption and storage through the first connecting pipe 200. Simultaneously, the connection path between the micro air pump 8 and the diagnostic chamber is cut off, ensuring that the fuel system remains sealed or under controlled pressure relief when the engine is not running, preventing the indiscriminate release of fuel vapor.

[0057] Furthermore, the second state of solenoid valve 1 is the normal state of integrated valve 700 when it is working in the fuel system, suitable for parking / pure electric driving conditions. In this condition, such as... Figure 4 As shown, when the fuel tank 100 is under negative pressure, the air can be filtered by the ash filter 800, and then fresh air is supplied to the charcoal canister 400 through the first pipe 4, the internal flow channel of the solenoid valve 1, the fourth flow channel 7, the second balance pipe 32, and the third flow channel 6. This fresh air is then supplied to the fuel tank 100 through the first connecting pipe 200, thus achieving pressure balance in the fuel tank 100. When it is not necessary to supply air to the fuel tank 100, and the fuel tank 100 is under positive pressure, the pressure inside the fuel tank 100 rises to the opening threshold of the first pressure balance valve 21. Then, the fuel vapor in the fuel tank 100 is adsorbed by the charcoal canister 400 and discharged to the atmosphere through the integrated valve 700, maintaining the pressure inside the fuel tank 100 within a safe range.

[0058] Furthermore, in some embodiments of this application, the fuel system further includes a second connecting pipe 500 and a charcoal canister solenoid valve 600 disposed on the second connecting pipe 500, the second connecting pipe 500 being connected between the charcoal canister 400 and the engine intake manifold.

[0059] The desorption / refueling condition refers to the desorption process required to recover fuel vapor from the charcoal canister 400 during engine operation, or the process of the user refueling and actively depressurizing the fuel tank 100. Under this condition, the controller 900 is configured to control the solenoid valve 1 to switch to the first state.

[0060] The desorption / refueling operation includes both desorption and refueling sub-operations, such as... Figure 5 As shown, in the desorption mode, the control solenoid valve 600 of the charcoal canister opens, and the negative pressure of the engine intake manifold is introduced through the second connecting pipe 500, drawing the fuel vapor adsorbed in the charcoal canister 400 into the engine for combustion. At this time, in order to balance the pressure in the charcoal canister 400, external clean gas passing through the ash filter 800 enters the charcoal canister 400 through the first pipe 4, the internal flow channel of the solenoid valve 1, the fourth pipe 7, the second balancing pipe 32, and the third pipe 6 to flush the charcoal canister 400. In the refueling / pressure relief mode, the high-pressure fuel-air mixture in the fuel tank 100 flows to the charcoal canister 400 through the first connecting pipe 200. After being adsorbed by activated carbon, the clean gas is discharged through the third pipe 6, the internal flow channel of the solenoid valve 1, and the first pipe 4. This pathway realizes the reuse of fuel vapor recovery and safe pressure relief functions during refueling.

[0061] Specifically, this application achieves automatic reconfiguration of fluid pathways under different vehicle operating scenarios through precise control of the solenoid valve 1 by the controller 900. When parked or in pure electric driving, the fuel system prioritizes environmental compliance and blocks direct emission paths; when the engine is running or refueling, the fuel system switches to flow mode to balance pressure or recover vapor; during leak diagnosis, the fuel system sequentially executes a pressure build-up-pressure holding logic sequence, first establishing a high-pressure environment using the micro air pump 8, and then closing the pipeline to observe the pressure drop. This condition-based pathway mapping mechanism allows a single integrated valve 700 to meet complex fuel system management needs, independently completing all-time leak monitoring preparation without relying on engine negative pressure.

[0062] Furthermore, in some embodiments of this application, the controller 900 is configured to diagnose whether there is a leak in the fuel system by comparing the pressure decay rate detected by the pressure sensor 300 within a first preset time period with a preset pressure decay threshold.

[0063] The first preset time period refers to any continuous time interval after the micro air pump 8 stops pumping pressure, the sealed diagnostic chamber is formed, and it enters the pressure holding state. The start and end points of this time interval can be set according to actual conditions, such as the first 30 seconds, 60 seconds, or longer after the pressure holding begins. This application embodiment does not make any special limitation on this. The length of the first preset time period determines the number of pressure sampling points and the stability of the calculation results. Within the first preset time period, the controller reads the values ​​of the pressure sensor 300 at a fixed sampling frequency, thereby constructing a pressure-time curve.

[0064] The pressure decay rate is obtained by linear fitting, differential calculation, or average rate of change calculation of multiple pressure values ​​collected within a first preset time period. In this embodiment, the pressure decay rate is a key physical quantity for quantifying the degree of leakage, and its value directly corresponds to the equivalent diameter of the leaking orifice. The pressure decay rate is calculated by the controller based on the pressure values ​​collected by the pressure sensor 300. If there is a leak in the sealed diagnostic chamber, the high-pressure gas inside the chamber will leak out over time, causing the pressure to decrease, thus generating a non-zero pressure decay rate.

[0065] The preset pressure decay threshold refers to a standard pressure change rate limit pre-stored in the controller 900's memory. This limit is a critical value obtained through experimental calibration or theoretical calculation based on the maximum permissible leakage amount required by regulations (e.g., equivalent diameter 0.50 mm). In the embodiments of this application, the preset pressure decay threshold serves as a baseline for determining whether the system is qualified. It is used to convert continuous pressure change data into a binary diagnostic conclusion. The preset pressure decay threshold and the pressure decay rate have the same dimension, and they logically form a comparative relationship. When the actual decay rate exceeds this threshold, it indicates that the leakage amount exceeds the permissible range.

[0066] Specifically, the working principle of this application is as follows: During the pressure holding phase of the diagnostic process, the controller controls the solenoid valve 1 to switch to the second state, forming a completely sealed diagnostic chamber with the fuel tank 100, charcoal canister 400, and related pipelines, and then shuts off the micro air pump 8. During a first preset time period, the controller 900 continuously reads the detection value from the pressure sensor 300. If there is a leak in the fuel system, the gas in the sealed diagnostic chamber will escape through the leak, causing the pressure in the sealed diagnostic chamber to decrease over time. The controller 900 uses a built-in algorithm to process the collected pressure sequence, calculates the actual pressure decay rate, and compares this rate with a preset pressure decay threshold. If the calculated pressure decay rate is less than or equal to the preset pressure decay threshold, the fuel system is determined to be well-sealed with no excessive leakage; if the calculated pressure decay rate is greater than the preset pressure decay threshold, the fuel system is determined to have a leakage fault.

[0067] In some embodiments of this application, the preset pressure attenuation threshold includes a first preset pressure attenuation threshold and a second preset pressure attenuation threshold that can be switched between each other, and the first preset pressure attenuation threshold is greater than the second preset pressure attenuation threshold. The controller 900 is configured to use the second preset pressure attenuation threshold as the preset pressure attenuation value when the ambient temperature is within the first preset temperature range, and to use the first preset pressure attenuation threshold as the preset pressure attenuation value when the ambient temperature is within the second preset temperature range. The second preset temperature range is higher than the first preset temperature range.

[0068] The preset pressure decay threshold can be a critical value for the rate of pressure change used to determine whether there is a leak in the fuel system. Its specific value can be set according to actual conditions, such as an empirical value calculated based on the pressure drop caused by a standard leak orifice within a specific time period. This application embodiment does not impose any special limitations on this. The first preset pressure decay threshold and the second preset pressure decay threshold can be two different numerical standards, with the first preset pressure decay threshold being greater than the second preset pressure decay threshold. Together, they constitute a dynamic criterion system adaptable to different environmental conditions. The switching relationship between the first preset pressure decay threshold and the second preset pressure decay threshold is automatically executed by the controller 900 based on the real-time monitored ambient temperature parameters to achieve adaptive adjustment of the diagnostic strategy.

[0069] The first preset temperature range refers to a relatively low ambient temperature range, such as -10℃ to +4℃. The specific boundary values ​​of this range can be set according to the applicable climate zone and regulatory requirements of the vehicle; this application embodiment does not impose any special limitations on this. The second preset temperature range is a normal ambient temperature range, such as +4℃ to +35℃, and the overall temperature level of the second preset temperature range is higher than that of the first preset temperature range. The division between the first and second preset temperature ranges is based on the differences in the physical properties of the gas and the performance of system components at different temperatures. These two temperature ranges serve as input conditions for the controller 900 to select the applicable threshold and are directly related to the selection logic of the preset pressure attenuation threshold, ensuring that matching diagnostic standards can be used in different temperature zones.

[0070] The integrated valve 700 has an integrally formed heat dissipation fin on the outside of the valve body. In the high-temperature diagnostic range of 35℃ to 45℃, the heat dissipation structure controls the temperature rise of the internal cavity of the valve body within the allowable range, eliminating the pressure drift interference caused by the thermal expansion of gas at high temperatures. Therefore, the controller 900 does not need to lower or correct the pressure drop judgment threshold in this high-temperature range. It directly uses the first preset pressure attenuation threshold. Only in the low-temperature range of -10℃ to +4℃, the attenuation threshold is lowered by 10% by software for compensation. The combination of software and hardware ensures the accuracy of leakage diagnosis across the entire temperature range.

[0071] Specifically, the working process and principle of this application are as follows: During the pressure holding phase of fuel system leak diagnosis, the controller 900 first acquires the current ambient temperature data. If the ambient temperature is detected to be within the first preset temperature range (low temperature range of -10℃ to +4℃), due to the higher air density at low temperatures, the gas outflow velocity under the same leak orifice diameter is relatively slow, resulting in a naturally lower pressure decay rate. If a conventional threshold is used, it is very easy to miss the detection. Therefore, the controller 900 automatically calls a second preset pressure decay threshold with higher sensitivity as the current criterion. This second preset pressure decay threshold is relatively small and can capture minute pressure changes. Conversely, if the ambient temperature is detected to be within the second preset temperature range (normal temperature range of +4℃ to +35℃), the first preset pressure decay threshold corresponding to the conventional environment can be directly used. Furthermore, when the ambient temperature is within the fourth preset temperature range, which is higher than the second preset temperature range (e.g., the high temperature range of +35℃ to +45℃), the high ambient temperature and the heat generated by the micro air pump 8 can easily cause the gas in the sealed diagnostic chamber to expand due to heat and the pressure to be falsely high. In this embodiment, the heat dissipation is achieved by the integrated heat dissipation fins of the valve body and the natural convection of the ambient air, which quickly dissipates the heat inside the valve body, suppresses the abnormal pressure rise of the gas in the chamber, and avoids misdiagnosis caused by high temperature thermal expansion. When the controller 900 reads the ambient temperature signal and determines that it falls into the high temperature range, it keeps the reference value of the left side of the first preset pressure attenuation threshold unchanged and does not perform threshold reduction compensation.

[0072] Through this temperature-range-based threshold dynamic switching mechanism, the fuel system can maintain the accuracy of diagnostic logic across the entire temperature range, eliminating interference from ambient temperature changes on diagnostic results.

[0073] Furthermore, it should be noted that, based on the original temperature and pressure compensation strategy, altitude compensation and fuel level compensation control logic have been added. The controller 900 connects to the vehicle navigation system to obtain real-time altitude parameters and connects to the fuel tank level sensor to collect real-time fuel level data. Based on the altitude and fuel level, it dynamically and adaptively corrects the target value of the diagnostic chamber pump pressure and the leakage judgment pressure attenuation threshold. This improvement only optimizes the control algorithm; the hardware structure of the integrated valve 700, the multi-position path control of the solenoid valve, the active pump pressure, and the core diagnostic logic of pressure holding and pressure drop remain unchanged. This effectively offsets the pressure measurement deviation caused by the low air pressure at high altitudes and the changes in the oil-gas space at high and low fuel levels, improving the accuracy of leakage diagnosis across all altitudes and fuel levels.

[0074] For example, the vehicle navigation module outputs altitude information. As the altitude increases and the ambient atmospheric pressure decreases, the controller 900 appropriately lowers the target value of the sealed diagnostic chamber pump pressure and simultaneously fine-tunes the pressure attenuation judgment threshold to compensate for the interference of low atmospheric pressure at high altitudes on the chamber pressure changes.

[0075] Alternatively, by collecting oil level signals through an oil tank level sensor, the pump pressure setpoint and pressure drop threshold can be dynamically corrected for two extreme operating conditions: ultra-high oil level and ultra-low oil level, thus eliminating pressure change errors caused by differences in the remaining volume of the oil tank.

[0076] like Figure 8 As shown in the embodiments of this application, a control method for the above-mentioned fuel system is also provided. This control method includes a fuel leak diagnosis method, which specifically includes the following steps: Step 1: Controller 900 controls solenoid valve 1 to switch to the third state. At this time, the second pipe 5 and the third pipe 6 are connected, and the first pipe 4 and the fourth pipe 7 are cut off. The oil tank 100, the charcoal canister 400 and the integrated valve 700 together form a sealed diagnostic chamber.

[0077] The controller 900 issues a command to switch the solenoid valve 1 to the third state, connecting the second pipe 5 (with the built-in miniature air pump 8) to the third pipe 6, while simultaneously cutting off the first pipe 4 and the fourth pipe 7. At this point, the oil tank 100, the first connecting pipe 200, the charcoal canister 400, the third pipe 6, the internal flow channel of the integrated valve 700, and the second pipe 5 together form a closed space, namely a sealed diagnostic chamber. The formation of this sealed diagnostic chamber eliminates interference from external air, ensuring the accuracy of subsequent pressure values ​​and providing the necessary physical basis for active pump pressure diagnosis.

[0078] Step 2: Control the miniature air pump 8 on the second pipe 5 to deliver gas into the sealed diagnostic chamber through the second pipe 5.

[0079] After the sealed diagnostic chamber is constructed, the controller activates the micro air pump 8 to deliver air into the sealed diagnostic chamber, causing the pressure inside the chamber to gradually increase from ambient pressure. The pressure sensor 300 is located in the first connecting pipe 200 or directly integrated into the oil tank 100 to monitor pressure changes inside the oil tank 100 in real time.

[0080] Specifically, the miniature air pump 8 operates in a constant flow or constant pressure mode, injecting gas into the sealed diagnostic chamber consisting of the oil tank 100, the carbon canister 400, and the pipeline. As the gas is injected, the internal pressure of the system increases linearly.

[0081] Step 3: Pressure sensor 300 acquires the pressure value of oil tank 100 in real time. When the pressure value reaches the preset diagnostic value, micro air pump 8 is turned off, and controller 900 controls solenoid valve 1 to switch to the second state. At this time, the first pipe 4 and the fourth pipe 7 are connected, and the second pipe 5 and the third pipe 6 are cut off.

[0082] Pressure sensor 300 acquires the current absolute pressure value at a high frequency (e.g., more than 10 times per second) and transmits this data to the controller in real time. For example, after the miniature air pump 8 has been operating for 10 seconds, the pressure value detected by pressure sensor 300 has increased from 101 kPa (ambient pressure) to 108 kPa. Through the combined use of miniature air pump 8 and pressure sensor 300, precise control and real-time quantitative monitoring of the pressurization process in the sealed diagnostic chamber are achieved, ensuring the controllability of the pump pressure stage and the continuity of data, and avoiding test failures caused by excessive pressure fluctuations.

[0083] The preset diagnostic value is the pressure threshold for determining the end of the pump pressure stage, typically set to the ambient pressure plus a fixed increment (e.g., ambient pressure +5kPa to +8kPa). When the real-time pressure value fed back by the pressure sensor 300 reaches this preset diagnostic value, the controller 900 immediately issues a command to shut down the miniature air pump 8, stopping pressurization. Next, to enter the pressure holding monitoring stage, the controller 900 again controls the solenoid valve 1 to switch to the second state, moving the valve core to the neutral position. In this position, the first pipe 4 and the fourth pipe 7 are connected (usually used for balancing or pressure relief preparation, but primarily to isolate the pump pressure path in the initial pressure holding stage), while the second pipe 5 and the third pipe 6 are cut off. This action disconnects the miniature air pump 8 from the sealed diagnostic chamber and also blocks the direct and rapid connection path between the sealed diagnostic chamber and the atmosphere (depending on the specific valve design, here it mainly refers to cutting off the pump pressure source and sealing the main body of the diagnostic chamber).

[0084] Step 4: The controller 900 compares the pressure decay rate detected by the pressure sensor 300 within the first preset time period with the preset pressure decay threshold, and diagnoses whether there is a leak in the fuel system based on the comparison result.

[0085] The first preset time period is the duration of pressure monitoring, typically set to at least 60 seconds to ensure sufficient pressure change data is collected to eliminate noise interference. During this period, pressure sensor 300 continues to record the pressure value within the diagnostic chamber. The pressure decay rate is the pressure drop per unit time (e.g., kPa / min), reflecting the system's sealing performance. The preset pressure decay threshold is the standard limit for determining leakage, and this threshold can be dynamically adjusted according to the ambient temperature (e.g., lowering the threshold at low temperatures, while maintaining the original threshold at normal and high temperatures).

[0086] Specifically, the controller 900 performs linear fitting or differential calculation on the pressure values ​​collected within a first preset time period to obtain the actual pressure decay rate. Then, it compares this pressure decay rate with a preset pressure decay threshold. If the actual decay rate is less than or equal to the preset pressure decay threshold, the fuel system is determined to be well-sealed and leak-free; if the actual decay rate is greater than the preset pressure decay threshold, a leak is determined to exist in the fuel system (e.g., a leak with an equivalent diameter greater than or equal to 0.50 mm), and the controller 900 generates a fault code and illuminates the instrument panel malfunction indicator light. For example, if the pressure drops from 108 kPa to 107.8 kPa within a 60-second monitoring period, and the calculated decay rate is 0.2 kPa / min, and the preset pressure decay threshold is 0.25 kPa / min, then no leak is determined. Through this comparison logic, a fully automatic closed loop from data acquisition to fault determination is achieved, accurately identifying even minor leaks without manual intervention.

[0087] Furthermore, a graded fault reporting strategy can be added to the leakage detection stage: after collecting the pressure decay rate during the pressure holding phase, the controller 900 classifies the leakage into two fault levels: minor leakage and severe leakage, based on the rate of decay. Different levels output corresponding fault codes and graded fault signals to the on-board diagnostic system (OBD). A slight pressure drop exceeding the preset pressure decay threshold indicates a minor leak, and the OBD stores the fault code and reminds the user to schedule maintenance. A pressure drop significantly exceeding the preset pressure decay threshold indicates a severe leak, and the OBD illuminates the fault indicator light, prompting immediate on-site maintenance.

[0088] Furthermore, in some embodiments of this application, the fuel leak diagnosis method further includes: confirming whether the current operating conditions meet the diagnostic conditions, and when the diagnostic conditions are met, controlling the solenoid valve to switch to a third state. The diagnostic conditions specifically include: a single parking time greater than a second preset time or the cumulative parking time since the last diagnosis is greater than a third preset time, the battery voltage being within a preset voltage range, the fuel level in the fuel tank 100 being within a preset level range, the ambient temperature being within a third preset temperature range, and no refueling operation occurring in the fuel tank 100.

[0089] The second preset time refers to the minimum duration threshold after the vehicle is turned off and stationary. Its function is to ensure that the thermodynamic state inside the fuel system reaches equilibrium and to eliminate pressure fluctuations caused by drastic temperature changes in the initial stage of engine shutdown. This time threshold is set based on the heat dissipation characteristics and gas thermal expansion coefficients of the fuel tank 100 and the piping system. For example, the second preset time can be set to 5 hours (300 minutes), meaning that only after the vehicle has been continuously parked for more than 5 hours is the internal temperature of the fuel system considered to be basically the same as the ambient temperature, and the pressure reading is considered to be stable.

[0090] Similarly, the third preset time refers to the threshold of the total cumulative parking time of the vehicle during subsequent use since the last leak diagnosis. Its purpose is to ensure that, under conditions of frequent vehicle use and insufficient single parking time, the cumulative effect of multiple parking periods is statistically analyzed to effectively meet the thermodynamic equilibrium condition, thus preventing the diagnosis from being triggered for an extended period due to insufficient single parking time. For example, the third preset time can be set to 10 hours. That is, when the cumulative parking time of the vehicle since the last diagnosis reaches 10 hours, even if no single parking session exceeds 5 hours, it is determined that the fuel system has achieved thermal equilibrium, allowing the next leak diagnosis to be initiated.

[0091] By setting the above-mentioned parking time constraints, it is possible to avoid initiating diagnostics when the vehicle has just been turned off and the fuel system is still in an unsteady state, thereby preventing false pressure attenuation signals caused by temperature differences and ensuring the reliability of the benchmark for subsequent pressure value acquisition.

[0092] The preset voltage range refers to the voltage interval within which the vehicle battery or high-voltage battery can drive the miniature air pump 8 and solenoid valve 1 within the integrated valve to operate normally. Its function is to ensure that the diagnostic actuator has sufficient power output and operational accuracy. This voltage range is determined based on the starting current requirements of the miniature air pump 8 and the holding voltage of the solenoid valve 1 coil. For example, the preset voltage range can be set to 11V to 16V. When the battery voltage is below 11V, the miniature air pump 8 may not be able to build sufficient diagnostic pressure, or the solenoid valve 1 spool may not switch properly, leading to sealing failure. When the voltage is above 16V, there may be a risk of electrical component overload. By monitoring the battery voltage in real time and limiting it within this range, the stability of the miniature air pump 8's gas delivery operation into the sealed diagnostic chamber and the accuracy of valve control are ensured during the diagnostic process, avoiding diagnostic interruptions or misjudgments due to insufficient power.

[0093] The preset fuel level range refers to the proportion of remaining fuel volume in the fuel tank 100 to the total volume. Its function is to ensure an appropriate vapor space volume within the diagnostic chamber, balancing detection sensitivity and system safety. This fuel level range is acquired in real-time by a fuel level sensor within the fuel tank 100. For example, the preset fuel level range can be set to 30% to 80% of the total volume. If the fuel level is below 30%, an excessively large vapor space may lead to slow pressure build-up and insignificant pressure changes caused by minor leaks, reducing detection sensitivity. If the fuel level is above 80%, an insufficient vapor space can easily cause system overpressure during active pumping, potentially triggering the safety valve to open or causing structural damage. By limiting the fuel level within this range, the sensitivity of the pressure decay rate to the leak orifice size is ensured, while the safety hazards caused by overcharging are avoided.

[0094] The third preset temperature range refers to the ambient temperature range suitable for high-precision pressure attenuation diagnosis. Its function is to match the operating characteristics of the pressure sensor 300 with the physical properties of the sealing material, reducing the interference of environmental factors on the diagnostic results. This temperature range is determined by combining the atmospheric density variation law and the thermal expansion and contraction characteristics of the rubber seal. For example, the third preset temperature range can be set to -10℃ to +45℃. Outside this temperature range, extremely low temperatures will cause a significant increase in air density and hardening and shrinkage of the seal, while extremely high temperatures may cause softening and creep of the seal and exacerbate the gas expansion effect, both of which will introduce system errors that are difficult to compensate for. By limiting the ambient temperature, the subsequent pressure attenuation threshold comparison becomes more accurate, effectively improving the diagnostic confidence across the entire temperature range.

[0095] No refueling operation refers to the state where the fuel tank cap 103 is not opened and no fuel refueling signal is detected during the diagnostic monitoring window. Its purpose is to eliminate interference from transient pressure releases and component changes caused by manually opening the fuel tank cap 103 or during the refueling process. This state is determined by the microswitch signal of the fuel tank cap 103 or the characteristics of sudden changes in fuel level. If a refueling operation is detected during the diagnostic preparation stage or execution, it means that the sealed diagnostic chamber has been damaged, the original pressure reference is invalid, and continued diagnosis will produce serious false alarms. By confirming no refueling operation, the integrity and continuity of the diagnostic chamber are ensured throughout the entire process from pump pressure to pressure holding monitoring, preventing invalid diagnoses caused by external disturbances.

[0096] These five conditions work together to trigger the diagnostic process only when the fuel system is in the optimal detection window. This not only significantly reduces the diagnostic failure rate caused by unsuitable operating conditions, but also avoids the risk of misdiagnosis caused by data collection under non-steady-state conditions, and significantly improves the first-pass rate and reliability of fuel evaporative emission leak diagnosis.

[0097] Furthermore, the fuel system control method also includes a fuel system pressure balance control method, which includes: When the fuel system is in a parking / pure electric driving condition, the control solenoid valve switches to the second state, and the micro air pump is turned off.

[0098] When the fuel tank 100 is under negative pressure, the atmosphere can be filtered using a ash filter. The filtered atmosphere then flows through the first pipe 4, the internal flow channel of the solenoid valve 1, the fourth flow channel 7, the second balancing pipe 32, and the third flow channel 6 to replenish fresh air into the charcoal canister 400. This fresh air then flows into the fuel tank 100 through the first connecting pipe 200, achieving pressure balance in the fuel tank 100. When there is no need to replenish the fuel tank 100, and the interior of the fuel tank 100 is under positive pressure, the pressure inside the fuel tank 100 rises to the opening threshold of the first pressure balancing valve 21. The fuel vapor in the fuel tank 100 is then adsorbed by the charcoal canister 400 and discharged into the atmosphere through the integrated valve 700, maintaining the pressure inside the fuel tank 100 within a safe range.

[0099] The control methods for the fuel system also include fuel system pressure relief control methods, which include: When the fuel system is in desorption / refueling mode, the control solenoid valve 1 switches to the first state and controls the micro air pump 8 to shut down.

[0100] In desorption mode, negative pressure in the engine intake manifold is introduced through the second connecting pipe 500, drawing fuel vapor adsorbed in the charcoal canister 400 into the engine for combustion. To balance the pressure in the charcoal canister 400, external clean gas passing through the ash filter 800 enters the charcoal canister 400 through the first pipe 4, the internal flow channel of the solenoid valve 1, the fourth pipe 7, the second balancing pipe 32, and the third pipe 6 to flush the charcoal canister 400. In refueling / pressure relief mode, the high-pressure fuel-air mixture in the fuel tank 100 flows to the charcoal canister 400 through the first connecting pipe 200. After adsorption by activated carbon, the clean gas is discharged through the third pipe 6, the internal flow channel of the solenoid valve 1, and the first pipe 4. This achieves the reuse of fuel vapor recovery and safe refueling pressure relief functions.

[0101] Furthermore, the fuel leak diagnosis method also includes acquiring the ambient temperature and setting a corresponding preset pressure decay threshold based on the acquired ambient temperature.

[0102] The ambient temperature can be acquired by the controller 900 through real-time acquisition of air temperature data around the vehicle via an onboard temperature sensor, or by reading existing ambient temperature signals from the vehicle's air conditioning system and battery thermal management system. This ambient temperature is a key variable determining the physical properties of fuel vapor and the performance of seals, directly affecting the natural law of pressure change over time within the sealed diagnostic chamber. Specifically, after receiving the ambient temperature data, the controller 900 uses it as an index parameter to look up or calculate a preset pressure decay threshold that matches the current temperature from a pre-stored mapping table. Because gas density and viscosity change with temperature, and the elastic modulus of rubber seals differs at different temperatures, the same leakage orifice diameter exhibits different pressure decay rates at different temperatures. Therefore, dynamically setting the threshold based on the acquired ambient temperature can eliminate diagnostic benchmark drift caused by ambient temperature differences. For example, when the detected ambient temperature is -5℃, the controller 900 automatically calls a lower pressure decay threshold suitable for the low-temperature range to compensate for the pressure fluctuation sensitivity caused by increased air density at low temperatures; while when the detected ambient temperature is 40℃, it calls a higher pressure decay threshold suitable for the high-temperature range to adapt to the softening of sealing materials and gas expansion characteristics at high temperatures. This threshold dynamic configuration mechanism based on real-time ambient temperature ensures that the diagnostic criteria are always consistent with the current physical environment, avoiding false alarms or missed alarms caused by fixed thresholds.

[0103] In practice, when the ambient temperature is within the first preset temperature range, the second preset pressure attenuation threshold is used as the preset pressure attenuation value.

[0104] The first preset temperature range can refer to the low-temperature environment range defined in the fuel system leak diagnosis strategy. This range typically covers the lower ambient temperature scenarios that the vehicle may encounter, such as -10℃ to +4℃. The second preset pressure decay threshold can refer to a pressure leak judgment standard value specifically set for the aforementioned low-temperature environment range. In low-temperature environments, due to increased air density and changes in the shrinkage characteristics of sealing materials, the natural pressure fluctuation characteristics inside the fuel system differ significantly from those in normal or high-temperature environments. If the judgment thresholds for normal or high-temperature ranges are directly used, false alarms can easily be triggered by small pressure fluctuations caused by environmental factors. Therefore, the second preset pressure decay threshold is set to a relatively small value to improve the sensitivity of the diagnostic system under low-temperature conditions. Specifically, after acquiring ambient temperature data, the controller 900 first determines whether the temperature falls within the first preset temperature range. If so, the controller 900 automatically calls and locks the second preset pressure decay threshold as the comparison benchmark for the current diagnostic cycle. For example, when the ambient temperature sensor detects a current ambient temperature of -5°C, which falls within the first preset temperature range of -10°C to +4°C, the controller 900 sets the preset pressure attenuation threshold to a second preset pressure attenuation threshold. This value is lower than the threshold for the conventional high-temperature range, thus ensuring accurate detection of minute leaks with an equivalent diameter greater than or equal to 0.50 mm under low-temperature conditions and avoiding missed diagnoses. This threshold reduction mechanism based on the low-temperature range effectively compensates for the impact of low temperatures on the gas state equation and sealing performance, ensuring consistent diagnostic results across the entire temperature range.

[0105] When the ambient temperature is within the second preset temperature range, the first preset pressure attenuation threshold is used as the preset pressure attenuation value. The second preset temperature range is higher than the first preset temperature range, and the second preset pressure attenuation threshold is less than the first preset pressure attenuation threshold.

[0106] The second preset temperature range can refer to the ambient temperature range defined in the fuel system leak diagnosis strategy, covering higher ambient temperature scenarios the vehicle may encounter, such as +4°C to +35°C. The first preset pressure decay threshold can refer to the pressure leak judgment standard value set for the aforementioned ambient temperature range. Under ambient temperature conditions, the first preset pressure decay threshold is set to a relatively large value, i.e., the judgment standard is relaxed. The second preset temperature range is generally higher than the first preset temperature range, and together they constitute a full-temperature diagnostic range covering the main regulatory requirements. At the same time, the value of the second preset pressure decay threshold is strictly smaller than the first preset pressure decay threshold, reflecting the differentiated compensation logic of low-temperature sensitivity and high-temperature tolerance. Specifically, when the controller determines that the ambient temperature falls within the second preset temperature range, it will use the first preset pressure decay threshold as the comparison benchmark.

[0107] When the ambient temperature is within the fourth preset temperature range, the first preset pressure attenuation threshold is used as the preset pressure attenuation value, and the fourth preset temperature range is higher than the second preset temperature threshold.

[0108] For example, when the ambient temperature sensor detects that the current ambient temperature is 40°C, which is within the second preset temperature range of +35°C to +45°C, the controller 900 still sets the preset pressure attenuation threshold to the first preset pressure attenuation threshold and reduces the temperature inside the sealed diagnostic cavity through the heat dissipation structure to achieve temperature compensation.

[0109] Furthermore, this application also provides a vehicle including a fuel system as described in the above embodiments, for executing the control methods described in the above embodiments.

[0110] The vehicle can be a means of transportation equipped with a power drive system and a fuel supply system. Its type can refer to a traditional internal combustion engine vehicle, or a hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV), or range-extended electric vehicle (EREV). In the embodiments of this application, the vehicle integrates the aforementioned fuel system to construct a complete fuel evaporation emission control and leak diagnosis system. The location of the fuel system in the vehicle can be set according to actual conditions. For example, it can be located in the area of ​​the vehicle chassis near the fuel tank 100, or it can be located at a specific mounting point on the vehicle body frame, as long as it facilitates pipeline connection, meets the vehicle's wading depth requirements, and adapts to the vehicle's vibration environment. This application embodiment does not impose any special limitations on this.

[0111] The fuel system is responsible for two main aspects: firstly, storing and transporting fuel, and treating fuel vapor adsorption and desorption to ensure normal vehicle operation under various conditions; secondly, utilizing integrated diagnostic functions, it actively monitors the fuel system's sealing performance at all times, including when the vehicle is parked, driving in pure electric mode, or running the engine. Specifically, components such as the integrated valve 700, pressure sensor 300, charcoal canister solenoid valve 600, and controller 900 in the fuel system establish communication or electrical connections with the vehicle's body control system, battery management system, and on-board diagnostic (OBD) system. When the vehicle is in different operating states, the fuel system can work independently or in conjunction with other vehicle systems to perform operations such as fuel injection, depressurization, pumping pressure, and pressure holding, thereby achieving accurate diagnosis of fuel evaporation and leakage.

[0112] Specifically, after the vehicle is equipped with this fuel system, its working process and principle are as follows: The vehicle's control unit (such as ECU or vehicle controller) determines whether the triggering conditions for leak diagnosis are met based on the vehicle's real-time operating conditions (such as parking time, battery voltage, fuel level, ambient temperature, etc.). Once the conditions are met, the vehicle initiates the diagnostic process, controlling the integrated valve in the fuel system to switch to a specific position, and cooperating with the built-in micro air pump 8 to pump pressure in the sealed diagnostic chamber composed of the fuel tank 100, charcoal canister 400, and pipelines, and monitoring pressure changes in real time through the pressure sensor 300. During this process, the vehicle can independently complete the diagnostic task without relying on the engine, especially under conditions where the vehicle is parked for a long time or only powered by electricity, it can still effectively monitor whether there are minor leaks in the fuel system. If the pressure decay rate is detected to exceed the preset pressure decay threshold, the vehicle will determine that there is a leak fault and issue a warning to the driver or maintenance personnel through the instrument panel or by storing fault codes, thereby ensuring that the vehicle complies with relevant emission regulations throughout its entire life cycle.

[0113] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0114] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An integrated valve, characterized in that, It includes a solenoid valve, a miniature air pump, a first pipe, a second pipe, a third pipe, and a fourth pipe, wherein the first pipe and the second pipe are located on one side of the solenoid valve, and the third pipe and the fourth pipe are located on the other side of the solenoid valve; The solenoid valve has switchable first, second, and third states. When the solenoid valve is in the first state, it connects the first and third pipes and disconnects the second and fourth pipes. When the solenoid valve is in the second state, it connects the first and fourth pipes and disconnects the second and third pipes. When the solenoid valve is in the third state, it connects the second and third pipes and disconnects the first and fourth pipes. The miniature air pump is located in the second pipeline and is used to deliver gas into the second pipeline when the solenoid valve is in the third state.

2. The integrated valve according to claim 1, characterized in that, It also includes a pressure balancing valve assembly and a pressure balancing pipeline. The pressure balancing valve assembly includes a first pressure balancing valve and a second pressure balancing valve. The pressure balancing pipeline includes a first balancing pipeline and a second balancing pipeline. The first pressure balancing valve is disposed in the first balancing pipeline, and the second pressure balancing valve is disposed in the second balancing pipeline. The first balancing pipeline and the second balancing pipeline are respectively connected to the third pipeline and the fourth pipeline. When the pressure in the third pipe is greater than the pressure in the fourth pipe, and the pressure difference is greater than the first preset pressure difference value, the first pressure balancing valve unilaterally connects the third pipe, the first balancing pipe, and the fourth pipe; when the pressure in the fourth pipe is greater than the pressure in the third pipe, and the pressure difference is greater than the second preset pressure threshold, the second pressure balancing valve unilaterally connects the fourth pipe, the second balancing pipe, and the third pipe.

3. A fuel system, characterized in that, The system includes a fuel tank, a charcoal canister, a first connecting pipe, a pressure sensor, a controller, and an integrated valve as described in any one of claims 1-2. The third pipe is connected to the charcoal canister, the fuel tank is connected to the charcoal canister through the first connecting pipe, the pressure sensor is located on the first connecting pipe, and the controller is connected to the integrated valve and the pressure sensor respectively, for controlling the integrated valve according to the operating conditions of the fuel system or the pressure detected by the pressure sensor.

4. The fuel system according to claim 3, characterized in that, The operating conditions of the fuel system include pre-diagnostic pump pressure condition and diagnostic pressure holding condition. In the pre-diagnosis pump pressure condition, the controller is configured to control the solenoid valve to switch to the third state and control the micro air pump to deliver gas into the second pipeline; During the diagnostic pressure holding condition, the controller is configured to control the solenoid valve to switch to the second state.

5. The fuel system according to claim 3, characterized in that, The operating conditions of the fuel system include a parking / pure electric driving condition. When the fuel system is in the parking / pure electric driving condition, the controller is configured to control the solenoid valve to switch to the second state. And / or, The operating conditions of the fuel system include desorption / refueling conditions. When the fuel system is in the desorption / refueling condition, the controller is configured to control the solenoid valve to switch to a first state.

6. The fuel system according to claim 5, characterized in that, The fuel system also includes a second connecting pipe and a charcoal canister solenoid valve. The second connecting pipe is connected between the charcoal canister and the engine intake manifold. The charcoal canister solenoid valve is located on the second connecting pipe and is used to open or close the second connecting pipe. The desorption / refueling conditions include a desorption sub-condition and a refueling sub-condition. When the fuel system is in the desorption sub-condition, the controller is configured to control the charcoal canister solenoid valve to open to connect the second connecting pipe. When the fuel system is in the refueling sub-condition, the controller is configured to control the charcoal canister solenoid valve to close to shut off the second connecting pipe.

7. A control method for a fuel system as described in any one of claims 3 to 6, characterized in that, The fuel system control method includes a fuel leak diagnosis method, which includes: The solenoid valve is switched to the third state, so that the oil tank, the charcoal canister, and the integrated valve together form a sealed diagnostic chamber; The micro air pump is controlled to deliver gas into the sealed diagnostic chamber through the second pipe; The pressure value of the sealed diagnostic chamber is acquired in real time. When the pressure value reaches the preset diagnostic value, the micro air pump is stopped and the solenoid valve is switched to the second state. The pressure decay rate of the sealed diagnostic chamber within a first preset time period is compared with the preset pressure decay threshold, and the presence of a leak in the fuel system is diagnosed based on the comparison result.

8. The control method for a fuel system according to claim 7, characterized in that, The fuel leak diagnosis method further includes: confirming whether the current operating conditions meet the diagnosis conditions, and when the diagnosis conditions are met, controlling the solenoid valve to switch to the third state; The diagnostic conditions include: a single parking time is greater than a second preset time or the cumulative parking time since the last diagnosis is greater than a third preset time, the battery voltage is within a preset voltage range, the fuel level in the fuel tank is within a preset level range, the ambient temperature is within a third preset temperature range, and there is no refueling operation in the fuel tank.

9. The control method for a fuel system according to claim 7, characterized in that, The fuel leak diagnosis method further includes obtaining the ambient temperature of the fuel system and setting a corresponding preset pressure attenuation threshold based on the obtained ambient temperature.

10. The control method for a fuel system according to claim 9, characterized in that, When the ambient temperature is within the first preset temperature range, the second preset pressure attenuation threshold is used as the preset pressure attenuation value. When the ambient temperature is within the second preset temperature range, the first preset pressure attenuation threshold is used as the preset pressure attenuation value. The second preset temperature range is higher than the first preset temperature range, and the second preset pressure attenuation threshold is less than the first preset pressure attenuation threshold.

11. The control method for a fuel system according to claim 7, characterized in that, The fuel system control method further includes a fuel system pressure balance control method, which includes: When the fuel system is in a parking / pure electric driving condition, the solenoid valve is switched to the second state, and the micro air pump is turned off.

12. The control method for a fuel system according to claim 7, characterized in that, The fuel system control method further includes a fuel system depressurization control method, which includes: When the fuel system is in desorption / refueling mode, the solenoid valve is switched to the first state, and the micro air pump is turned off.

13. A vehicle, characterized in that, Used to perform the control method of the fuel system as described in any one of claims 7 to 12.

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