Fuel system for range-extended vehicle

Abstract

The utility model provides a fuel system for a range-extended vehicle, and belongs to the field of electronic control technology for a range-extended vehicle fuel system. The design of the fuel system for a range-extended vehicle that the fuel tank cap can be manually unscrewed after the air pressure sensing device detects that the air pressure in the fuel tank is lower than a limit value solves the problems of complex control logic and high production cost of the fuel system in the prior art. The fuel system for a range-extended vehicle comprises a fuel tank and a fuel vapor absorption device connected by an isolation valve, the isolation valve is controlled to open and close by an electronic controller on the vehicle, a fuel tank port for refueling is provided on the fuel tank, a fuel tank cap is provided at the fuel tank port, and the fuel tank cap is provided with an air pressure sensing device, and the fuel tank cap can be manually opened after the air pressure sensing device detects that the air pressure in the fuel tank is lower than a limit value.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic control of a fuel system of a range-extended vehicle, in particular to a fuel system of a range-extended vehicle. Background Art

[0002] An extended-range electric vehicle is a unique hybrid vehicle that integrates an internal combustion engine into a pure electric vehicle to provide additional charging capacity for the power battery or directly drive the motor, thereby significantly extending the vehicle's range. The range extender part of an extended-range electric vehicle consists of a small-displacement engine and a generator directly connected to it. The small-displacement engine provides kinetic energy through the combustion of gasoline in the high-pressure fuel tank. When refueling, in order to prevent the refueler from opening the fuel tank cap in advance and being burned by the fuel vapor sprayed back from the high-pressure fuel tank, the existing technology uses a fuel system composed of components such as an electronic controller, a pressure sensor, a fuel tank, and an isolation valve, and cooperates with the fuel system control logic to control the opening and closing of the electric small door.

[0003] The existing fuel system control logic is: the electronic controller converts the refueling switch's signal to refuel into an instruction, controls the opening of the isolation valve between the fuel tank and the carbon canister, and when the fuel vapor in the fuel tank is fully released into the carbon canister through the isolation valve, the pressure sensor connected to the fuel tank detects that the air pressure in the fuel tank is lower than the limit value, and sends a signal to the electronic controller to control the electric small door to open and refuel. This fuel system control logic is relatively complex, and a special program needs to be designed to control the electric small door. In addition, the electric small door has a complex structure and needs to be controlled by the vehicle controller, which has high production costs. Utility Model Content

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present utility model is to provide a fuel system for a range-extended vehicle, which is used to solve the problems of complex control logic and high production cost of the fuel system in the prior art.

[0005] To achieve the above-mentioned purpose and other related purposes, the utility model provides a fuel system for a range-extended vehicle, comprising a fuel tank and a fuel vapor absorption device connected by an isolation valve, wherein the isolation valve is controlled to open and close by an electronic controller on the vehicle, the fuel tank is provided with a fuel tank port for refueling, a fuel tank cap is provided at the fuel tank port, and the fuel tank cap is provided with an air pressure sensing device, and after the air pressure sensing device detects that the air pressure in the fuel tank is lower than a limited value, the fuel tank cap can be manually opened.

[0006] Optionally, the fuel vapor absorption device is a carbon canister, and an ash filter is provided on the carbon canister.

[0007] Optionally, the fuel tank cap includes a threaded seat that closes the fuel tank port, the upper end of the threaded seat is connected to a screw part, and a separation device for separating the screw part and the threaded seat is installed inside the threaded seat; the air pressure sensing device is a pressure relief valve installed at the lower end of the threaded seat, and when the pressure relief valve is opened, the screw part is separated from the threaded seat through the separation device.

[0008] Optionally, when the pressure relief valve is opened, the separation device drives the screw member to separate from the threaded seat; when the pressure relief valve is closed, the screw member and the threaded seat are connected through the separation device and rotate together.

[0009] Optionally, a gear ring is fixedly installed inside the threaded seat; the separation device includes a spring, and both ends of the spring are respectively connected to the screw part and the linkage shaft; when the spring naturally expands and contracts, the gear ring and the linkage shaft restrict each other and rotate together; when the pressure relief valve opens, the oil and gas rushing out of the oil tank drives the linkage shaft to compress the spring upward, and the linkage shaft and the gear ring are out of restriction.

[0010] Optionally, a diaphragm is installed inside the threaded seat, and the diaphragm seals and isolates the separation device and the pressure relief valve, and the separation device also includes a push rod; the bottom of the push rod is fixedly connected to the diaphragm, and the top of the push rod passes through the gear ring and is connected to the linkage shaft; the diaphragm bulges upward due to the action of oil and gas rushing out of the oil tank, driving the push rod to push up the linkage shaft to compress the spring.

[0011] Optionally, the gear ring includes an outer ring and an inner ring, the outer wall of the outer ring is fixedly fitted with the inner wall of the threaded seat, and the inner wall of the outer ring is meshed with the outer wall of the inner ring; when the spring naturally expands and contracts, the top of the inner ring and the linkage shaft restrict each other and rotate together.

[0012] Optionally, the diaphragm is bowl-shaped; when the pressure relief valve is closed, the bottom of the bowl-shaped diaphragm and the inner bottom of the threaded seat are completely fitted, and the top outer edge of the bowl-shaped diaphragm and the inner wall of the threaded seat are sealed and connected.

[0013] Optionally, a screw post is provided at the top of the screwing member, a spring groove for accommodating the spring is provided in the screwing member, and the spring groove is provided in the screw post.

[0014] Optionally, a column opening is opened at the top of the screw column, a dust plug is installed at the column opening, and the fuel tank cap is equipped with a forced opening column, and the diameter of the forced opening column is smaller than the diameter of the column opening.

[0015] As described above, the fuel system for a range-extended vehicle of the utility model has at least the following beneficial effects:

[0016] 1. The fuel system of the range-extended vehicle is designed to manually unscrew the fuel tank cap after the air pressure sensing device detects that the air pressure in the fuel tank is lower than the specified value. Compared with the prior art, the electronic controller receives the signal from the pressure sensor connected to the fuel tank, and then opens the electric small door at the fuel tank port after the pressure sensor sends a signal that the air pressure in the fuel tank is lower than the specified value. The utility model does not require the electronic controller on the vehicle to control the opening of the electric small door. The control logic of the fuel system is relatively simple, and there is no need to design a special program to control the electric small door. Moreover, because the fuel tank cap of the utility model is simpler in structure than the electric small door of the prior art, the production cost of the fuel system of the range-extended vehicle of the utility model is lower.

[0017] 2. The fuel tank cap of the fuel system of the range-extended vehicle is closed by the pressure relief valve, and the screw drives the threaded seat to rotate together; when the pressure relief valve is opened, the screw cannot drive the threaded seat to rotate, so that when the oil and gas pressure in the tank is too high, the refueling personnel can only rotate the screw in idling mode when turning the screw, and only when the oil and gas pressure in the tank is reduced to the point where the pressure relief valve is closed, can the screw drive the threaded seat to rotate when the screw is turned, thereby opening the tank port; this prevents the refueling personnel from being burned by high-pressure oil and gas when opening the threaded seat when the oil and gas pressure in the tank is too high; at the same time, compared with the electric fuel tank cap, this fuel tank cap does not contain relatively complex and high-cost components such as motors and wiring harnesses, and does not require the use of additional electronic control logic, effectively controlling the production cost of the range extender of the range-extended vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Shown is a schematic diagram of a fuel system for a range-extended vehicle according to the present utility model.

[0019] Figure 2 Shown is a schematic diagram of the fuel tank cap of the present invention.

[0020] Figure 3 Shown is a cross-sectional view of the fuel tank cap of the present invention.

[0021] Figure 4 Shown is a step diagram of a control method for a range-extended vehicle fuel system according to the present invention.

[0022] Figure 5 A step diagram showing a control method for a fuel system of a range-extended vehicle in the prior art.

[0023] Component number description

[0024] Fuel tank cap 0, threaded seat 1, gear ring 11, outer ring 111, inner ring 112, diaphragm 12, separation device 2, spring 21, linkage shaft 22, push rod 23, screw part 3, screw column 31, dust plug 32, pressure relief valve 4, sealing ring 5, fuel tank 6, fuel tank port 61, carbon canister 7, ash filter 71, isolation valve 8. DETAILED DESCRIPTION

[0025] The following is a description of the implementation of the present invention by means of specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0026] See also Figures 1 to 5 . It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the utility model, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects and purposes that can be achieved by the utility model, should still fall within the scope of the technical content disclosed by the utility model. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the utility model. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the utility model without substantially changing the technical content.

[0027] The following embodiments are only for illustration purposes and can be combined with each other, and are not limited to the contents presented in the following single embodiments.

[0028] See also Figure 1 The utility model provides a fuel system for a range-extended vehicle, comprising a fuel tank 6 and a fuel vapor absorption device connected through an isolation valve 8, the isolation valve 8 being controlled to open and close by an electronic controller (ECU) on the vehicle, the fuel tank 6 being provided with a fuel tank port 61 for refueling, the fuel tank port 61 being provided with a fuel tank cap 0, the fuel tank cap 0 being provided with an air pressure sensing device, and the fuel tank cap 0 being able to be manually unscrewed after the air pressure sensing device detects that the air pressure in the fuel tank is lower than a limited value; the design that the fuel tank cap 0 can be manually unscrewed after the air pressure sensing device detects that the air pressure in the fuel tank is lower than a limited value Compared with the prior art, after the electronic controller receives the signal from the pressure sensor connected to the fuel tank 6, after the pressure sensor sends a signal that the air pressure in the fuel tank 6 is lower than the limit value, the electronic controller opens the electric small door of the fuel tank port 61. The utility model does not require the electronic controller on the vehicle to control the opening of the electric small door. The control logic of the fuel system is relatively simple, and there is no need to design a special program to control the electric small door. Moreover, because the structure of the fuel tank cap 0 is simpler than the electric small door of the prior art, the production cost of the extended-range vehicle fuel system of the utility model is lower.

[0029] In another embodiment, see Figure 1The fuel vapor absorption device is a carbon canister 7, and an ash filter 71 is provided on the carbon canister 7. The carbon canister 7 is a common fuel vapor absorption device, which uses the adsorption function of activated carbon to store the fuel vapor overflowing from the fuel tank 6. The ash filter 71 is used to prevent dust from entering the interior of the carbon canister 7.

[0030] In another embodiment, the on-board automatic diagnostic system (OBD) of the prior art vehicle does not need to start the engine when performing diagnostic work, but needs to inflate the fuel system through the fuel evaporation system leakage detection pump (DMTL pump) to form a positive pressure for diagnosis; however, because the DMTL pump is expensive, the OBD of the utility model replaces the DMTL pump with a carbon canister 7 shut-off valve and a small-range sensor when performing diagnostic work, and by starting the engine, the fuel system is evacuated to form a negative pressure for diagnosis, which has lower production costs.

[0031] In another embodiment, see Figures 1 to 3 The fuel tank cap 0 includes a threaded seat 1 that closes the fuel tank port 61. A separation device 2 is installed inside the threaded seat 1, a screw 3 is connected to the upper end, and a pressure relief valve 4 is installed at the lower end. When the pressure relief valve 4 is opened, the separation device 2 drives the screw 3 to separate from the threaded seat 1. When the pressure relief valve 4 is closed, the screw 3 and the threaded seat 1 are connected and rotated together. The design of the fuel tank cap 0 opening by the pressure relief valve 4, the separation device 2 drives the screw 3 to separate from the threaded seat 1, the pressure relief valve 4 is closed, and the screw 3 and the threaded seat 1 are connected and rotated together makes it possible for the refueling personnel to rotate the screw 3 only when the oil and gas pressure in the fuel tank 6 is too high, because the screw 3 and the threaded seat 1 are separated, and only when the oil and gas pressure in the fuel tank 6 is reduced to the pressure relief valve 4 is closed, can the screw seat 1 be driven to rotate when the screw 3 is turned, thereby opening the fuel tank port 61; to avoid the refueling personnel from being burned by the high-pressure oil and gas when opening the threaded seat 1 when the oil and gas pressure in the fuel tank 6 is too high.

[0032] At present, extended-range electric vehicles generally use electric fuel tank caps. When refueling, the ECU (electronic controller) needs to detect that the fuel tank pressure has dropped to a certain pressure, and then issue a command to let the electric fuel tank cap open to prevent the refueling personnel from opening the fuel tank cap in advance when the pressure in the fuel tank is too high, causing injury to the refueling personnel. However, the cost of this electric small door is too high. Compared with the fuel tank cap 0 of the utility model, it contains relatively complex and high-cost components such as motors and wiring harnesses, and requires the use of additional electronic control logic, which has a higher production cost.

[0033] In another embodiment, see Figure 3A gear ring 11 is fixedly installed inside the threaded seat 1; the separation device 2 includes a spring 21, and the two ends of the spring 21 are respectively connected to the screw member 3 and the linkage shaft 22, and the linkage shaft 22 rotates together with the screw member 3; when the oil and gas pressure in the fuel tank 6 is lower than the limit value, the pressure relief valve 4 is closed, and the linkage shaft 22 is not subjected to the action of external force, the spring 21 is in a state of natural expansion and contraction, and the gear ring 11 and the linkage shaft 22 restrict each other. When the refueling personnel screws the screw member 3, the screw member 3 and the linkage shaft 22 rotate together, and drive the threaded seat 1 to rotate together through the mutual restriction with the gear ring 11, so that the threaded seat 1 is removed from the tank port 61, and the refueling personnel refuels the fuel tank 6 from the tank port 61.

[0034] like Figure 3 As shown, when the oil and gas pressure in the fuel tank 6 is higher than the specified value, the pressure relief valve 4 opens, and the oil and gas rushing out of the fuel tank 6 drives the linkage shaft 22 to compress the spring 21 upward, and the spring 21 brings the linkage shaft 22 and the gear ring 11 out of the limit. In this way, when the refueling personnel turns the screw part 3, the screw part 3 can only rotate idly, but cannot rotate with the threaded seat 1 to open the fuel tank port 61, thereby avoiding the high-pressure oil and gas rushing out of the fuel tank port 61 to cause harm to the refueling personnel. The entire structure is all mechanical and the production cost is relatively low.

[0035] In another embodiment, see Figure 3 A diaphragm 12 is installed inside the threaded seat 1, and the diaphragm 12 seals and isolates the separation device 2 from the pressure relief valve 4. The separation device 2 also includes a push rod 23; the bottom of the push rod 23 is fixedly connected to the diaphragm 12, and the top of the push rod 23 passes through the gear ring 11 and is connected to the linkage shaft 22; the diaphragm 12 is upwardly protruded by the oil and gas rushing out of the fuel tank 6, driving the push rod 23 to push the linkage shaft 22 upward to compress the spring 21. The structure of the separation device 2 is further refined through the design of the diaphragm 12 and the push rod 23. In addition, due to the design of the diaphragm 12, the oil and gas in the fuel tank 6 are isolated by the diaphragm 12 and will not rush into the interior of the threaded seat 1. While playing a certain protective role on the components inside the threaded seat 1, it also prevents the oil and gas from spraying out through some gaps on the upper part of the threaded seat 1, causing damage to people or objects around the fuel tank cap 0.

[0036] In another embodiment, see Figure 3The gear ring 11 includes an outer ring 111 and an inner ring 112. The outer wall of the outer ring 111 is fixedly fitted with the inner wall of the threaded seat 1, and the inner wall of the outer ring 111 is meshed with the outer wall of the inner ring 112; when the spring 21 naturally expands and contracts, the top of the inner ring 112 and the linkage shaft 22 restrict each other and rotate together. The gear ring 11 is designed as an inner ring 112 and an outer ring 111 to reduce the difficulty of production. The production of a gear ring 11 fixedly installed inside the threaded seat 1 and cooperating with the linkage shaft 22 requires a high overall strength of the gear ring 11, and the mass of the entire gear ring 11 is also large, and the production cost is high. If the gear ring 11 is designed as a form in which an outer ring 111 and an inner ring 112 cooperate, then as long as the inner ring 112 and the outer ring 111 are produced separately and then assembled as required, the production cost can be effectively controlled.

[0037] In another embodiment, see Figure 3 The diaphragm 12 is bowl-shaped; when the pressure relief valve 4 is closed, the bottom of the bowl-shaped diaphragm 12 is completely fitted with the inner bottom of the threaded seat 1, and the top outer edge of the bowl-shaped diaphragm 12 is sealed with the inner wall of the threaded seat 1, which not only seals the oil and gas, but also provides a temporary accommodating chamber for the high-pressure oil and gas rushing out of the fuel tank 6, thereby improving the reliability of the operation of the fuel tank cap.

[0038] In another embodiment, see Figure 2 and Figure 3 A screw post 31 is provided at the top of the screw part 3, and a spring groove for accommodating the spring 21 is provided in the screw part 3. The spring groove is provided in the screw post 31 to limit the direction of compression and extension of the spring 21, thereby improving the reliability of the working of the fuel tank cap 0 and making it convenient for the refueling personnel to unscrew the fuel tank cap 0.

[0039] In another embodiment, see Figure 3 A column opening is provided at the top of the screw column 31. When the fuel tank 6 fails to relieve pressure, the screwing piece 3 and the threaded seat 1 are always out of contact, resulting in the fuel tank cap 0 being unable to be opened, a stick that can be inserted from the column opening can be used to press the linkage shaft 22 downward, so that the screwing piece 3 and the threaded seat 1 can rotate together after being restricted by each other, thereby forcing the fuel tank cap 0 to be opened, avoiding the problem of failure to refuel due to failure to relieve pressure in the fuel tank 6.

[0040] In another embodiment, see Figure 3 A dust plug 32 is installed at the column mouth to prevent dust from entering the interior of the threaded seat 1 from the column mouth and causing adverse effects on the operation of the components inside the threaded seat 1.

[0041] In another embodiment, see Figure 3, and then design a strong opening column, the diameter of which is smaller than the diameter of the column mouth, so that when the fuel tank 6 fails to release pressure, the refueling personnel do not need to look for a stick that can be inserted into the column mouth, and can directly use the equipped strong opening column to solve the problem.

[0042] In another embodiment, see Figure 3 A sealing ring 5 is installed on the outer wall of the threaded seat 1. When the threaded seat 1 closes the fuel tank opening 61, the sealing ring 5 is pressed and fitted to the periphery of the fuel tank opening 61 by the threaded seat 1, thereby improving the sealing effect of the fuel tank cap 0 on the fuel tank opening 61.

[0043] In other embodiments, Figure 3 As shown, there are multiple pressure relief valves 4. When one pressure relief valve 4 is damaged, the reliability of the fuel tank cap 0 can still be guaranteed under the operation of other pressure relief valves 4.

[0044] like Figure 4 As shown, a control method for a fuel system of a range-extended vehicle based on the above-mentioned method includes the following steps:

[0045] S1: When the vehicle is short of oil, the refueling switch is pressed, and after the electronic controller receives the refueling instruction from the refueling switch on the vehicle, it controls the isolation valve 8 to open;

[0046] S2: The fuel vapor in the fuel tank 6 enters the carbon canister 7 through the isolation valve 8, and the gas pressure in the fuel tank 6 decreases;

[0047] S3: When the air pressure sensing device on the mailbox cover detects that the air pressure in the fuel tank 6 is lower than the limit value, the pressure relief valve 4 no longer discharges fuel vapor into the threaded seat, and the screw 3 is turned to drive the threaded seat to rotate, thereby opening the fuel tank port 61 and refueling the fuel tank.

[0048] like Figure 5 As shown, in the prior art, after the pressure sensor detects that the air pressure in the fuel tank 6 is lower than the limit value, the electronic controller on the vehicle controls the opening of the electric door. The entire control method includes the following steps:

[0049] S1: When the vehicle is short of oil, the refueling switch is pressed, and after the electronic controller receives the refueling instruction from the refueling switch, it controls the isolation valve 8 to open;

[0050] S2: The fuel vapor in the fuel tank 6 enters the carbon canister 7 through the isolation valve 8, and the gas pressure in the fuel tank 6 decreases;

[0051] S3: The pressure sensor detects that the gas pressure in the fuel tank 6 is lower than the limit value;

[0052] S4: The pressure sensor sends a signal that the gas pressure in the fuel tank 6 is lower than the limit value to the electronic controller;

[0053] S5: The electronic controller issues a command to control the electric small door to open according to a specially designed program.

[0054] Obviously, the utility model provides a fuel system for a range-extended vehicle, which has a simpler control logic and fewer steps.

[0055] In summary, the utility model is designed to manually unscrew the fuel tank cap 0 after the air pressure sensing device detects that the air pressure in the fuel tank is lower than the limit value. Compared with the prior art, after the electronic controller receives the pressure sensor signal connected to the fuel tank 6, after the pressure sensor sends a signal that the air pressure in the fuel tank 6 is lower than the limit value, the electronic controller opens the electric small door of the fuel tank port 61. The utility model does not require the electronic controller on the vehicle to control the opening of the electric small door. The control logic of the fuel system is relatively simple, and there is no need to design a special program to control the electric small door. Moreover, because the structure of the fuel tank cap 0 is simpler than the electric small door of the prior art, the production cost of the extended-range vehicle fuel system of the utility model is lower, the control logic is simpler, and the steps are fewer. Therefore, the utility model effectively overcomes the shortcomings of the prior art and has a high industrial utilization value.

[0056] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed in the present invention shall still be covered by the claims of the present invention.

Claims

1. A fuel system for a range-extended vehicle, comprising a fuel tank and a fuel vapor absorption device connected by an isolation valve, the isolation valve being opened and closed by an electronic controller on the vehicle, the fuel tank being provided with a fuel tank port for refueling, and a fuel tank cap being provided at the fuel tank port, characterized in that: The fuel tank cover is provided with an air pressure sensing device. After the air pressure sensing device detects that the air pressure in the fuel tank is lower than a limited value, the fuel tank cover can be opened manually.

2. A fuel system for a range-extended vehicle according to claim 1, characterized in that: The fuel vapor absorption device is a carbon canister, and an ash filter is arranged on the carbon canister.

3. A fuel system for a range-extended vehicle according to claim 1, characterized in that: The fuel tank cap comprises a threaded seat for closing the fuel tank opening, the upper end of the threaded seat is connected to a screwing piece, and a separation device for separating the screwing piece and the threaded seat is installed inside the threaded seat; The air pressure sensing device is a pressure relief valve installed at the lower end of the threaded seat. When the pressure relief valve is opened, the screwing member is separated from the threaded seat through the separation device.

4. A fuel system for a range-extended vehicle according to claim 3, characterized in that: When the pressure relief valve is opened, the separation device drives the screw member to separate from the threaded seat; when the pressure relief valve is closed, the screw member and the threaded seat are connected through the separation device and rotate together.

5. A fuel system for a range-extended vehicle according to claim 4, characterized in that: A gear ring is fixedly installed inside the threaded seat; the separation device includes a spring, and the two ends of the spring are respectively connected to the screwing member and the linkage shaft; When the spring expands and contracts naturally, the gear ring and the linkage shaft are restricted to rotate together; when the pressure relief valve is opened, the oil and gas rushing out of the oil tank drive the linkage shaft to compress the spring upward, and the linkage shaft and the gear ring are out of restriction.

6. A fuel system for a range-extended vehicle according to claim 5, characterized in that: A diaphragm is installed inside the threaded seat, and the diaphragm seals and isolates the separation device and the pressure relief valve, and the separation device also includes a push rod; The bottom of the push rod is fixedly connected to the diaphragm, and the top of the push rod passes through the gear ring and is connected to the linkage shaft; the diaphragm bulges upward under the action of the oil and gas rushing out of the oil tank, driving the push rod to push up the linkage shaft to compress the spring.

7. A fuel system for a range-extended vehicle according to claim 5, characterized in that: The gear ring comprises an outer ring and an inner ring, the outer wall of the outer ring is fixedly fitted with the inner wall of the threaded seat, and the inner wall of the outer ring is meshed with the outer wall of the inner ring; When the spring expands and contracts naturally, the top of the inner ring and the linkage shaft are constrained to rotate together.

8. The fuel system for a range-extended vehicle according to claim 6, characterized in that: The diaphragm is bowl-shaped; when the pressure relief valve is closed, the bottom of the bowl-shaped diaphragm and the inner bottom of the threaded seat are completely fitted, and the top outer edge of the bowl-shaped diaphragm and the inner wall of the threaded seat are sealed and connected.

9. A fuel system for a range-extended vehicle according to claim 5, characterized in that: A screw post is arranged on the top of the screwing part, a spring slot for accommodating the spring is arranged in the screwing part, and the spring slot is arranged in the screw post.

10. A fuel system for a range-extended vehicle according to claim 9, characterized in that: A column opening is provided at the top of the screwing column, a dust plug is installed at the column opening, and the fuel tank cover is equipped with a forced opening column, the diameter of which is smaller than the diameter of the column opening.

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