A fuel evaporation control system and its control method

Abstract

This invention discloses a fuel evaporation control system and its control method, relating to the field of automotive and motorcycle fuel system technology. To address the safety and environmental pollution issues of existing fuel evaporation control systems, the system includes a fuel tank with a first connecting pipe and a second connecting pipe. The insertion port of the first connecting pipe is lower than that of the second connecting pipe. A fuel tank cap connects to the fuel tank and a carbon canister. A fuel tank cap connector is connected to the first connecting pipe via a first pipe. An on / off valve is connected to the fuel tank cap connector. The on / off valve includes a valve body with an air passage and a first interface and a second interface communicating with the air passage. The first interface is connected to a second pipe, and the second interface is connected to the second connecting pipe via a third pipe. A valve core assembly for controlling the on / off connection between the first and second interfaces is provided within the air passage. An elastic element provides a preload force to move the valve core assembly closer to the fuel tank cap. This design is safer and more environmentally friendly.

Description

Technical Field

[0001] This invention relates to the field of automotive and motorcycle fuel system technology, and more specifically, to a fuel evaporation control system and its control method. Background Technology

[0002] Currently, the fuel evaporation control system mainly consists of a fuel tank, fuel evaporation rubber hose, tilt valve, carbon canister, throttle valve, and engine. This system is more suitable for external fuel tanks that are completely exposed to the air. However, for internal fuel tanks that are completely surrounded by vehicle body panels, the heat dissipation environment is poor, which poses a risk of fuel evaporation control system failure.

[0003] The main problems include poor fuel tank cooling, fuel tank pressure exceeding 15 kPa in hot summer weather, fuel expansion with increasing temperature and pressure, and the inability of the carbon canister to completely desorb fuel vapors after it becomes saturated, leading to excess fuel vapors being cooled and liquefied by the wind and polluting the atmosphere. When the engine is turned off and restarted, excessive fuel evaporation results in an overly rich air-fuel mixture that remains in the throttle valve, making starting difficult. When refueling with more than one-third of the fuel remaining in the tank requires opening the fuel tank cap, the high-temperature, high-pressure fuel vaporizes into a mist and is sprayed out instantly, posing a safety risk.

[0004] Therefore, how to solve the problems of low safety and environmental pollution in existing fuel evaporation control systems is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a fuel evaporation control system that can avoid the safety problem of fuel vaporizing into mist and spraying out of the fuel tank filler neck instantly during the high temperature and high pressure fuel evaporation process, and can also prevent excess fuel vapor from being cooled and condensed by the wind from the other side of the carbon canister vent wall and flowing out to pollute the atmospheric environment.

[0006] Another objective of this invention is to provide a fuel evaporation control method that includes the above-described fuel evaporation control system, which is safer and more environmentally friendly.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A fuel evaporation control system, comprising:

[0009] The fuel tank is provided with a first connecting pipe and a second connecting pipe, wherein the insertion port of the first connecting pipe is lower than the insertion port of the second connecting pipe.

[0010] The fuel tank cap is equipped with a fuel tank cap connector for connecting the fuel supply pipe. The fuel supply pipe is connected to the fuel tank. One side of the fuel tank cap connector is connected to the first connecting pipe through the first pipe, and the other side of the fuel tank cap connector is connected to the carbon canister through the pipe.

[0011] The on / off valve is connected to the fuel tank cap connector. The on / off valve includes a valve body, and the valve body has an air passage extending along its own axis inside. The valve body has a first interface and a second interface communicating with the air passage in its circumference. The first interface is connected to a pipeline through a second pipe, and the second interface is connected to a second connecting pipe through a third pipe. The air passage has a valve core assembly for controlling the on / off of the first interface and the second interface. One end of the valve core assembly abuts against the fuel tank cap, and the other end of the valve core assembly is connected to an elastic element. The elastic element is used to provide a preload force to move the valve core assembly closer to the fuel tank cap.

[0012] Preferably, the valve core assembly includes a push rod with a first shoulder and a second shoulder. The cavity between the first shoulder and the second shoulder is used to connect the first interface and the second interface. One end of the push rod abuts against the fuel tank cap, and the other end of the push rod is connected to an elastic element. The elastic element is used to provide a preload force to move the push rod closer to the fuel tank cap so that the first shoulder blocks the second interface.

[0013] Preferably, the outer periphery of the second shoulder is provided with an annular groove, and the outer periphery of the first shoulder is provided with two annular grooves, with the two annular grooves respectively located at both ends of the first shoulder, and a sealing element is provided in the annular groove.

[0014] Preferably, the first inner cavity, formed by the depth of the first connecting pipe inserted into the inner cavity of the fuel tank and the area overlapping with the fuel tank at the same depth, has a volume of 15% of the total volume of the fuel tank, and the inner cavity of the fuel delivery pipe has a volume of 10% of the total volume of the fuel tank.

[0015] Preferably, the depth to which the second connecting pipe is inserted into the inner cavity of the fuel tank, and the volume of the second inner cavity formed by the region overlapping the fuel tank to the same depth, is 5% of the total volume of the fuel tank.

[0016] Preferably, the pipeline includes a fourth pipe, a tee pipe, a fifth pipe, and a sixth pipe. One end of the fourth pipe is connected to the other side of the fuel tank cap connector, and the other end of the fourth pipe is connected to one interface of the tee pipe. The other two interfaces of the tee pipe are connected to the fifth pipe and the second pipe, respectively. The fifth pipe is connected to a tilt valve, and the tilt valve is connected to the carbon canister through the sixth pipe.

[0017] Preferably, the carbon canister is connected to a throttle valve via a seventh pipe, and the throttle valve is connected to the engine.

[0018] Preferably, a one-way valve is provided on the seventh pipeline. The opening pressure of the one-way valve is greater than the outlet pressure of the carbon canister and less than the absolute value of the negative pressure at the front end of the throttle valve.

[0019] Preferably, all seals are rubber rings.

[0020] Preferably, both the first connecting pipe and the second connecting pipe are metal pipes, and both the first connecting pipe and the second connecting pipe are welded to the fuel tank as a whole.

[0021] Preferably, the elastic element is a spring.

[0022] A fuel evaporation control method, applied to the fuel evaporation control system described in any one of the above, the fuel evaporation control method comprising:

[0023] Add fuel to the fuel tank, open the fuel tank cap, and the elastic element pushes the valve core assembly upward to disconnect the first interface from the second interface. The air in the fuel tank is discharged through the first connecting pipe, the first pipeline, the fuel tank cap joint, the pipeline and the carbon canister.

[0024] Close the fuel tank cap and push the valve core assembly down to connect the first interface with the second interface. Air in the fuel tank is discharged through the second connecting pipe, the third pipe, the on / off valve, the second pipe, the pipeline, and the carbon canister.

[0025] Preferably, during the refueling process, fuel enters the fuel tank through the fuel tank cap connector and the fuel delivery pipe. When the amount of fuel flowing into the fuel tank reaches the insertion port of the first connecting pipe, the insertion port of the first connecting pipe is sealed by fuel to prevent air from flowing out of the fuel tank. The area above the insertion port of the first connecting pipe in the fuel tank is the remaining air, which is sealed in the upper part of the fuel tank. Fuel continues to be added until the fuel delivery pipe is full.

[0026] Preferably, after the fuel tank cap is closed, as the air inside the fuel tank is discharged through the second connecting pipe, the third pipe, the on / off valve, the second pipe, the pipeline and the carbon canister, the fuel inside the fuel delivery pipe flows into the fuel tank under the action of gravity.

[0027] The fuel evaporation control system provided by this invention includes a fuel tank, a first connecting pipe, a second connecting pipe, a fuel tank cap, a fuel tank cap connector, a fuel delivery pipe, a carbon canister, and an on / off valve. Specifically, the fuel tank cap is provided with a fuel tank cap connector connected to the fuel delivery pipe. The fuel tank cap, fuel tank cap connector, fuel delivery pipe, and fuel tank form a refueling channel. During refueling, fuel flows to the fuel tank through the fuel delivery pipe. The fuel tank is provided with a first connecting pipe and a second connecting pipe, and the insertion port of the first connecting pipe is lower than the insertion port of the second connecting pipe. One side of the fuel tank cap connector is connected to the first connecting pipe through a first pipe, and the other side of the fuel tank cap connector is connected to the carbon canister through a pipe, so that air in the fuel tank can be discharged sequentially through the first connecting pipe, the first pipe, the fuel tank cap connector, the pipe, and the carbon canister.

[0028] The on / off valve is connected to the fuel tank cap connector. The on / off valve includes a valve body with an axially extending air passage inside to allow gas flow. The valve body has a first interface and a second interface circumferentially connected to the air passage. The first interface is connected to a pipeline via a second pipe, and the second interface is connected to a second connecting pipe via a third pipe. The air passage contains a valve core assembly for controlling the on / off state of the first and second interfaces. The valve core assembly controls the connection state of the second and third pipes. One end of the valve core assembly abuts against the fuel tank cap, and the other end of the valve core assembly is connected to an elastic element. The elastic element provides a preload force to move the valve core assembly closer to the fuel tank cap. When the fuel tank cap is opened, the elastic element pushes the valve core assembly upward to disconnect the first and second interfaces, thus preventing the second and third pipes from connecting. This blocks the air in the fuel tank from entering the fuel tank cavity and the third pipe. At this time, the air in the fuel tank cavity can only pass through the first connecting pipe, the first pipe, the fuel tank cap connector, and the pipeline in sequence, and finally exit from the carbon canister.

[0029] After refueling is complete, the fuel line is filled with fuel, and the insertion port of the first connecting pipe is sealed with fuel to prevent air from flowing out. At this time, the fuel tank cap is closed, and the fuel tank cap pushes the valve core assembly down, compressing the elastic element and connecting the first and second interfaces. This connects the second and third pipes, allowing air in the fuel tank to pass through the second connecting pipe, the third pipe, the second interface, the on / off valve, the first interface, the second pipe, and the pipeline in sequence, finally being discharged from the carbon canister. As the air in the fuel tank is discharged, space is created inside the fuel tank, and fuel in the fuel line flows into the fuel tank under the action of gravity to fill the fuel tank.

[0030] By installing a first connecting pipe and a second connecting pipe inside the fuel tank, and installing a fuel delivery pipe and an on / off valve outside it, an effective space volume for the evaporation and expansion of fuel under high temperature and high pressure is formed. This prevents the fuel tank from becoming too hot due to insufficient space for fuel evaporation and expansion, which would cause a large amount of fuel vapor to evaporate and spray out from the filler neck, causing safety problems, or flowing into the carbon canister and being cooled and condensed by the wind, causing pollution problems. This achieves the goals of safety and environmental protection. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the structure of the fuel evaporation control system provided by the present invention;

[0033] Figure 2 This is a cross-sectional view of the fuel tank provided by the present invention;

[0034] Figure 3 A cross-sectional view of the on / off valve provided by the present invention;

[0035] Figure 4 A cross-sectional view of the on / off valve when the fuel tank cap is opened, provided by the present invention;

[0036] Figure 5 This is a cross-sectional view of the on / off valve when the fuel tank cap is closed, provided by the present invention.

[0037] Figure 6 This is a flowchart illustrating the steps of the fuel evaporation control method provided by the present invention.

[0038] Figure label:

[0039] 1-Fuel tank; 2-First connecting pipe; 3-Second connecting pipe; 4-Fuel tank cap; 5-Fuel tank cap connector; 6-Fuel supply pipe; 7-First pipeline; 8-Carbon canister; 9-On / off valve; 91-Valve body; 92-First interface; 93-Second interface; 94-Elastic element; 95-Push rod; 96-First shoulder; 97-Second shoulder; 98-Seal; 10-Second pipeline; 11-Third pipeline; 12-Fourth pipeline; 13-Tee pipe; 14-Fifth pipeline; 15-Sixth pipeline; 16-Tilting valve; 17-Seventh pipeline; 18-Throttle valve; 19-Check valve. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0042] It should be noted that the directional terms such as "up" and "down" in the following text are defined based on the accompanying drawings in the instruction manual.

[0043] The core of this invention is to provide a fuel evaporation control system that avoids the safety problem of fuel vaporizing into a mist and instantly spraying out from the fuel filler neck of the fuel tank 1 during the high-temperature and high-pressure fuel evaporation process. It also prevents excess fuel vapor from being cooled and condensed by wind from the vent wall on the other side of the carbon canister 8, thus preventing it from polluting the atmosphere. Another core aspect of this invention is to provide a fuel evaporation control method that includes the above-mentioned fuel evaporation control system, which is safer and more environmentally friendly.

[0044] Please refer to Figure 1 , Figure 2 and Figure 3 A fuel evaporation control system includes a fuel tank 1, a first connecting pipe 2, a second connecting pipe 3, a fuel tank cap 4, a fuel tank cap connector 5, a fuel delivery pipe 6, a carbon canister 8, and an on / off valve 9.

[0045] Specifically, the fuel tank cap 4 is equipped with a fuel tank cap connector 5 that connects to the fuel supply pipe 6. The fuel tank cap 4, fuel tank cap connector 5, fuel supply pipe 6 and fuel tank 1 are connected to form a refueling channel. When refueling, fuel flows to the fuel tank 1 through the fuel supply pipe 6. The fuel tank 1 is equipped with a first connecting pipe 2 and a second connecting pipe 3. The insertion port of the first connecting pipe 2 is lower than the insertion port of the second connecting pipe 3. One side of the fuel tank cap connector 5 is connected to the first connecting pipe 2 through the first pipe 7, and the other side of the fuel tank cap connector 5 is connected to the carbon canister 8 through the pipe, so that the air in the fuel tank 1 can be discharged in sequence through the first connecting pipe 2, the first pipe 7, the fuel tank cap connector 5, the pipe and the carbon canister 8.

[0046] The on / off valve 9 is connected to the fuel tank cap connector 5. The on / off valve 9 includes a valve body 91. The valve body 91 has an air passage extending along its own axis to allow gas flow. The valve body 91 has a first interface 92 and a second interface 93 communicating with the air passage in its circumferential direction. The first interface 92 is connected to a pipeline through a second pipe 10, and the second interface 93 is connected to a second connecting pipe 3 through a third pipe 11. The air passage has a valve core assembly for controlling the on / off state of the first interface 92 and the second interface 93. The valve core assembly controls the connection state of the second pipe 10 and the third pipe 11. One end of the valve core assembly is connected to the fuel tank cap. 4. The other end of the valve core assembly is connected to the elastic element 94. The elastic element 94 is used to provide a preload force to move the valve core assembly closer to the fuel tank cap 4. When the fuel tank cap 4 is opened, the elastic element 94 pushes the valve core assembly upward so that the first interface 92 is disconnected from the second interface 93, thereby making the second pipe 10 and the third pipe 11 disconnected. This blocks the air in the fuel tank 1 from entering the fuel tank 1 cavity and the third pipe 11. At this time, the air in the fuel tank 1 cavity can only pass through the first connecting pipe 2, the first pipe 7, the fuel tank cap joint 5 and the pipeline in sequence, and finally be discharged from the carbon canister 8.

[0047] After refueling is completed, the fuel supply pipe 6 is filled with fuel, and the insertion port of the first connecting pipe 2 is sealed with fuel to prevent air from flowing out of the first connecting pipe 2. At this time, the fuel tank cap 4 is closed, and the fuel tank cap 4 pushes the valve core assembly down, causing the elastic element 94 to be compressed. At the same time, the first interface 92 and the second interface 93 are connected, so that the second pipe 10 and the third pipe 11 are connected. The air in the fuel tank 1 passes through the second connecting pipe 3, the third pipe 11, the second interface 93, the on / off valve 9, the first interface 92, the second pipe 10 and the pipeline in sequence, and finally exits from the carbon canister 8. While the air in the fuel tank 1 is being discharged, space is made in the inner cavity of the fuel tank 1. The fuel in the fuel supply pipe 6 flows into the fuel tank 1 under the action of gravity to fill the fuel tank 1.

[0048] By installing a first connecting pipe 2 and a second connecting pipe 3 inside the fuel tank 1, and installing an oil supply pipe 6 and an on / off valve 9 outside it, an effective space volume for the evaporation and expansion of fuel under high temperature and high pressure is formed. This prevents the fuel tank 1 from becoming too hot due to insufficient space for evaporation and expansion, which would cause a large amount of fuel vapor to evaporate and spray out from the filler neck, causing safety problems, or flowing into the carbon canister 8 and being cooled and condensed by the wind, causing pollution problems. This achieves the purpose of safety and environmental protection.

[0049] The on / off valve 9 is connected to the oil tank cap connector 5 by bolts, but in actual application, this is not restricted.

[0050] The fuel evaporation control system designed in the above manner seals the air in the third pipe 11 and part of the inner cavity of the fuel tank 1 during the refueling process when the fuel tank cap 4 is opened. After the fuel is filled, the air in the third pipe 11 and the inner cavity of the fuel tank 1 is opened, and the fuel filled in the inner cavity of the fuel delivery pipe 6 flows back into the inner cavity of the fuel tank 1 under the action of gravity. The top of the fuel delivery pipe 6 and part of the inner cavity of the fuel tank 1 is filled with air, which becomes the space volume for fuel evaporation and expansion, thus solving the problem of fuel evaporation. This structure is simple, easy to manufacture, durable and reliable.

[0051] Please refer to Figure 4 and Figure 5 The valve core assembly includes a push rod 95, on which a first shoulder 96 and a second shoulder 97 are provided. The cavity between the first shoulder 96 and the second shoulder 97 is used to connect the first interface 92 and the second interface 93. One end of the push rod 95 abuts against the oil tank cover 4, and the other end of the push rod 95 is connected to an elastic member 94. The elastic member 94 is used to provide a preload force to move the push rod 95 toward the oil tank cover 4 so that the first shoulder 96 blocks the second interface 93.

[0052] It should be noted that when the fuel tank cap 4 is opened, the push rod 95 moves towards the fuel tank cap 4 under the action of the elastic element 94, that is, moves upward, so that the first shoulder 96 blocks the second interface 93 to seal the third pipe 11, so that the air in the inner cavity of the fuel tank 1 is blocked in the third pipe 11 and the inner cavity of the fuel tank 1, and will not be discharged through the third pipe 11 and the on / off valve 9. When the fuel tank cap 4 is closed, the fuel tank cap 4 pushes the push rod 95 downward, so that the first interface 92 and the second interface 93 are connected to conduct the third pipe 11 and the second pipe 10, so that the air in the inner cavity of the fuel tank 1 can be discharged through the third pipe 11, the on / off valve 9 and the second pipe 10.

[0053] In the above situation, the outer periphery of the second shoulder 97 is provided with an annular groove, the outer periphery of the first shoulder 96 is provided with two annular grooves, and the two annular grooves are respectively provided at both ends of the first shoulder 96, and a sealing element 98 is provided in the annular groove.

[0054] Understandably, the three seals 98 are fitted into the three annular grooves of the shoulder of the push rod 95, and then the push rod 95 is installed into the inner cavity of the valve body 91. The seals 98 are used to seal the shoulder and the inner cavity of the valve body 91, thereby restricting airflow.

[0055] Furthermore, the first inner cavity volume formed by the depth of the first connecting pipe 2 inserted into the inner cavity of the fuel tank 1 and the overlapping depth of the fuel tank 1 is 15% of the total volume of the fuel tank 1, the inner cavity volume of the fuel supply pipe 6 is 10% of the total volume of the fuel tank 1, and the second inner cavity volume formed by the depth of the second connecting pipe 3 inserted into the inner cavity of the fuel tank 1 and the overlapping depth of the fuel tank 1 is 5% of the total volume of the fuel tank 1.

[0056] Understandably, when refueling, when the amount of fuel flowing into the inner cavity of the fuel tank 1 reaches the insertion port of the first connecting pipe 2, the insertion port of the first connecting pipe 2 is sealed by fuel to prevent air from flowing out. The area above the insertion port of the first connecting pipe 2 in the inner cavity of the fuel tank 1 is where the remaining air is sealed in the upper part of the inner cavity of the fuel tank 1. The inner cavity of the fuel tank 1 is completely filled with most of the fuel and a small amount of air. When refueling continues, the inner cavity of the fuel tank 1 is completely filled with most of the fuel and a small amount of air until the fuel fills the inner cavity of the fuel supply pipe 6 connected to the fuel tank 1. When the fuel tank cap 4 is closed, the airflow inside the fuel tank 1 is connected and discharged through the second connecting pipe 3, the third pipe 11, the on / off valve 9, and the second pipe 10. The volume vacated during the process of the airflow inside the fuel tank 1 being discharged to the atmosphere is 15% of the total volume of the fuel tank 1. The fuel stored in the fuel delivery pipe 6 is 10% of the total volume of the fuel tank 1. The volume vacated during the process of the airflow inside the fuel tank 1 being discharged to the atmosphere is completely filled by the fuel stored in the fuel delivery pipe 6 under its own gravity. Therefore, at this time, the remaining 5% of the total volume of the fuel tank 1, which is the air space at the top of the fuel tank 1, is set as the fuel evaporation expansion space and volume of the fuel tank 1.

[0057] Based on the above embodiment, the pipeline includes a fourth pipe 12, a tee pipe 13, a fifth pipe 14, and a sixth pipe 15. One end of the fourth pipe 12 is connected to the other side of the fuel tank cap connector 5, and the other end of the fourth pipe 12 is connected to one interface of the tee pipe 13. The other two interfaces of the tee pipe 13 are respectively connected to the fifth pipe 14 and the second pipe 10. The fifth pipe 14 is connected to the tilt valve 16, and the tilt valve 16 is connected to the carbon canister 8 through the sixth pipe 15.

[0058] It should be noted that when refueling, the fuel tank cap 4 is opened, and the elastic element 94 in the on / off valve 9 pushes the push rod 95 upward. The first shoulder 96 of the push rod 95 seals the airflow at the lower end of the valve body 91, and the sealing element 98 on the second shoulder 97 seals the airflow at the upper end of the push rod 95. The internal air passage of the on / off valve 9 is closed. The air in the inner cavity of the fuel tank 1 is blocked by the on / off valve 9 after passing through the second connecting pipe 3 and the third pipe 11. During the fuel injection process, the air blocked in the inner cavity of the fuel tank 1 is gradually discharged from the first connecting pipe 2, the first pipe 7, the fuel tank cap 4, the fourth pipe 12, the three-way pipe 13, the fifth pipe 14, the tilt valve 16, the sixth pipe 15, and the carbon canister 8 vent. When the amount of fuel flowing into the inner cavity of fuel tank 1 reaches the insertion port of the first connecting pipe 2, the insertion port of the first connecting pipe 2 is sealed by fuel to prevent air from flowing out. The area above the insertion port of the first connecting pipe 2 in the inner cavity of fuel tank 1 is the remaining air, which is sealed in the upper part of the inner cavity of fuel tank 1. The inner cavity of fuel tank 1 is completely filled with most of the fuel and a small amount of air. The volume of the inner cavity of fuel pipe 6 is 5% of the total volume of fuel tank 1, that is, the remaining air space at the top of fuel tank 1 is the expansion amount after the amount of fuel injected into the inner cavity of fuel tank 1. When fuel is continued to be added from the fuel tank 1 opening, the inner cavity of fuel tank 1 is completely filled with most of the fuel and a small amount of air until the fuel fills the inner cavity of fuel pipe 6 connected to fuel tank 1. When the inner cavity of fuel pipe 6 is full of fuel, the refueling nozzle will click off, and the user can visually determine that the fuel is full.

[0059] When the fuel tank cap 4 is closed, the fuel tank cap 4 pushes the push rod 95 down to compress the elastic element 94. When the fuel tank cap 4 is fully closed, the cavity between the two shoulders of the push rod 95 forms a clearance fit with the inner cavity of the valve body 91. The cavity gap between the first shoulder 96 and the second shoulder 97 forms an airflow channel with the third pipe 11 and the second pipe 10. The airflow in the inner cavity of the fuel tank 1 is gradually discharged to the atmosphere from the second connecting pipe 3, the third pipe 11, the on / off valve 9, the second pipe 10, the three-way pipe 13, the fifth pipe 14, the tilt valve 16, the sixth pipe 15 and the carbon canister 8 vent. The volume of the fuel tank 1 vacated during the airflow discharge process is completely filled by the fuel in the inner cavity of the fuel pipe 6 under the action of the fuel gravity. The volume of the inner cavity of the fuel pipe 6 and 5% of the total volume of the fuel tank 1, i.e., the remaining top air space of the fuel tank 1, is set as the fuel evaporation expansion space and volume in the fuel tank 1.

[0060] The fuel tank 1 is equipped with a first connecting pipe 2, a second connecting pipe 3, and an external fuel supply pipe 6, which, together with the on / off valve 9, form an effective space volume for the evaporation and expansion of fuel under high temperature and high pressure. This prevents the pressure inside the fuel tank 1 from rising due to insufficient space for fuel evaporation and expansion in high-temperature weather, resulting in a large amount of fuel vapor evaporating and flowing into the carbon canister 8. This completely solves the safety problem of fuel vaporizing into mist and spraying out of the fuel filler neck of the fuel tank 1 during the high temperature and high pressure fuel evaporation process, as well as the problem of excess fuel vapor being cooled and condensed by the wind from the other side of the vent wall of the carbon canister 8, polluting the atmospheric environment.

[0061] In the above embodiment, the carbon canister 8 is connected to the throttle valve 18 via the seventh pipe 17, and the throttle valve 18 is connected to the engine.

[0062] Understandably, by setting the throttle valve 18, the flow rate of fuel gas from the carbon canister 8 to the engine can be controlled.

[0063] As a preferred embodiment, a one-way valve 19 is provided on the seventh pipe 17. The opening pressure of the one-way valve 19 is greater than the outlet pressure of the carbon canister 8 and less than the absolute value of the negative pressure at the inlet of the throttle valve 18.

[0064] It should be noted that during a period of riding in high temperatures, the carbon canister 8 adsorbs a rich mixture of vaporized fuel and air-fuel mixture. When the vehicle is turned off and restarted, the excessively rich vaporized fuel mixture enters due to the negative pressure at the intake front of the throttle valve 18, making it difficult to start the engine. Therefore, a one-way valve 19 is installed between the carbon canister 8 and the throttle valve 18. The pressure of the one-way valve 19 must be greater than the pressure at the carbon canister 8 inlet and less than the absolute value of the negative pressure at the intake front of the throttle valve 18. The one-way valve 19 prevents the excessively rich vaporized fuel mixture from entering the throttle valve 18 and the engine. The pressure of the one-way valve 19 is less than the absolute value of the negative pressure at the intake front of the throttle valve 18 to ensure that the vaporized fuel mixture is completely desorbed into the engine fuel to perform work, thus solving the problem of difficult starting.

[0065] In the above cases, all seals 98 are rubber rings.

[0066] It is understandable that the seal 98 can be a rubber ring, but in practical applications, it can also be other structures, and there are no restrictions on this.

[0067] In the above embodiments, both the first connecting pipe 2 and the second connecting pipe 3 are metal pipes, and both the first connecting pipe 2 and the second connecting pipe 3 are welded to the fuel tank 1 as a whole.

[0068] It should be noted that the first connecting pipe 2 and the second connecting pipe 3 are welded together with the fuel tank 1.

[0069] In the above embodiment, the elastic element 94 is a spring.

[0070] It is understood that in this embodiment, the elastic element 94 is preferably a spring, but in practical applications, it can also be set as other structures, and there is no limitation on this.

[0071] Please refer to Figure 6 A fuel evaporation control method, applied to the aforementioned fuel evaporation control system, the fuel evaporation control method comprising:

[0072] Step S1: Add fuel to fuel tank 1, open fuel tank cap 4, and let elastic element 94 push valve core assembly upward so that first interface 92 and second interface 93 are disconnected. Air in fuel tank 1 is discharged through first connecting pipe 2, first pipe 7, fuel tank cap joint 5, pipeline and carbon canister 8.

[0073] Step S2: Close the fuel tank cap 4 and push the valve core assembly down so that the first interface 92 and the second interface 93 are connected. The air in the fuel tank 1 is discharged through the second connecting pipe 3, the third pipe 11, the on / off valve 9, the second pipe 10, the pipeline and the carbon canister 8.

[0074] It should be noted that when the fuel tank cap 4 is opened, the valve core assembly moves towards the fuel tank cap 4 under the action of the elastic element 94, that is, moves upward, so that the first interface 92 and the second interface 93 are disconnected, and the air in the inner cavity of the fuel tank 1 is blocked in the third pipe 11 and the inner cavity of the fuel tank 1, and will not be discharged through the third pipe 11 and the on / off valve 9. At the same time, the air in the fuel tank 1 can be discharged through the first connecting pipe 2, the first pipe 7, the fuel tank cap connector 5, the pipeline and the carbon canister 8. When the fuel tank cap 4 is closed, the fuel tank cap 4 pushes the valve core assembly downward, so that the first interface 92 and the second interface 93 are connected, so as to conduct the third pipe 11 and the second pipe 10, and the air in the inner cavity of the fuel tank 1 can be discharged through the second connecting pipe 3, the third pipe 11, the on / off valve 9, the second pipe 10, the pipeline and the carbon canister 8.

[0075] Based on the above embodiment, during the refueling process of fuel tank 1, fuel enters fuel tank 1 through fuel tank cap connector 5 and fuel supply pipe 6. When the amount of fuel flowing into the inner cavity of fuel tank 1 reaches the insertion port of the first connecting pipe 2, the insertion port of the first connecting pipe 2 is sealed by fuel to prevent air from flowing out of the inner cavity of fuel tank 1. The area above the insertion port of the first connecting pipe 2 in the inner cavity of fuel tank 1 is the remaining air, which is sealed in the upper part of the inner cavity of fuel tank 1. Fuel continues to be added until the inner cavity of fuel supply pipe 6 is filled with fuel.

[0076] Furthermore, after the fuel tank cap 4 is closed, during the process of the air in the inner cavity of the fuel tank 1 being discharged through the second connecting pipe 3, the third pipe 11, the on / off valve 9, the second pipe 10, the pipeline and the carbon canister 8, the fuel in the inner cavity of the fuel delivery pipe 6 flows into the fuel tank 1 under the action of gravity. At this time, the volume of the inner cavity of the fuel delivery pipe 6 and 5% of the total volume of the fuel tank 1, i.e., the remaining top air space of the fuel tank 1, are set as the fuel evaporation expansion space and volume in the fuel tank 1.

[0077] In summary, the fuel evaporation control system provided by this invention completely solves the safety problems caused by the fuel vaporization into mist and instantaneous spraying from the fuel tank 1 filler neck during the high temperature and high pressure fuel evaporation process, as well as the problem of excess fuel vapor being cooled and condensed by the wind from the other side of the carbon canister 8 vent wall, polluting the atmospheric environment. It also completely solves the problem of excessive fuel evaporation causing the air-fuel mixture to be too rich and remain in the throttle valve 18, making it difficult to start.

[0078] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0079] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0080] The present invention provides a detailed description of a fuel evaporation control system and its control method. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of these embodiments are merely for the purpose of helping to understand the method and core ideas of the invention. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A fuel evaporation control system, characterized in that, include: A fuel tank (1) is provided with a first connecting pipe (2) and a second connecting pipe (3), wherein the insertion port of the first connecting pipe (2) is lower than the insertion port of the second connecting pipe (3); The fuel tank cap (4) is provided with a fuel tank cap connector (5) for connecting the fuel supply pipe (6). The fuel supply pipe (6) is connected to the fuel tank (1). One side of the fuel tank cap connector (5) is connected to the first connecting pipe (2) through the first pipe (7). The other side of the fuel tank cap connector (5) is connected to the carbon canister (8) through a pipeline. The pipeline includes a fourth pipe (12), a three-way pipe (13), a fifth pipe (14), and a sixth pipe (15). A shut-off valve (9) is connected to the fuel tank cap connector (5). The shut-off valve (9) includes a valve body (91). The valve body (91) has an air passage extending along its own axis inside. The valve body (91) has a first interface (92) and a second interface (93) communicating with the air passage in the circumferential direction. The first interface (92) is connected to the three-way pipe (13) through the second pipe (10). The second interface (93) is connected to the second connecting pipe (3) through the third pipe (11). The air passage has a valve core assembly for controlling the opening and closing of the first interface (92) and the second interface (93). One end of the valve core assembly abuts against the fuel tank cap (4). The other end of the valve core assembly is connected to an elastic element (94). The elastic element (94) is used to provide a preload force to move the valve core assembly closer to the fuel tank cap (4). The first connecting pipe (2) is inserted into the inner cavity of the fuel tank (1) to a depth equal to the depth of the fuel tank (1), and the volume of the first inner cavity formed by the overlapping area of ​​the fuel tank (1) is 15% of the total volume of the fuel tank (1). The volume of the inner cavity of the oil delivery pipe (6) is 10% of the total volume of the fuel tank (1). The second connecting pipe (3) is inserted into the inner cavity of the fuel tank (1) to a depth equal to the depth of the fuel tank (1), and the volume of the second inner cavity formed by the region that overlaps with the fuel tank (1) is 5% of the total volume of the fuel tank (1).

2. The fuel evaporation control system according to claim 1, characterized in that, The valve core assembly includes a push rod (95), on which a first shoulder (96) and a second shoulder (97) are provided. The cavity between the first shoulder (96) and the second shoulder (97) is used to connect the first interface (92) and the second interface (93). One end of the push rod (95) abuts against the oil tank cover (4), and the other end of the push rod (95) is connected to the elastic member (94). The elastic member (94) is used to provide a preload force to move the push rod (95) toward the oil tank cover (4) so ​​that the first shoulder (96) blocks the second interface (93).

3. The fuel evaporation control system according to claim 2, characterized in that, The second shoulder (97) has an annular groove on its outer periphery, and the first shoulder (96) has two annular grooves on its outer periphery, and the two annular grooves are respectively located at both ends of the first shoulder (96). A seal (98) is provided in the annular groove.

4. The fuel evaporation control system according to claim 1, characterized in that, One end of the fourth pipe (12) is connected to the other side of the oil tank cap connector (5), and the other end of the fourth pipe (12) is connected to one interface of the three-way pipe (13). The other two interfaces of the three-way pipe (13) are connected to the fifth pipe (14) and the second pipe (10) respectively. The fifth pipe (14) is connected to the tilt valve (16), and the tilt valve (16) is connected to the carbon canister (8) through the sixth pipe (15).

5. The fuel evaporation control system according to claim 4, characterized in that, The carbon canister (8) is connected to a throttle valve (18) via a seventh pipe (17), and the throttle valve (18) is connected to the engine.

6. The fuel evaporation control system according to claim 5, characterized in that, The seventh pipe (17) is equipped with a one-way valve (19). The opening pressure of the one-way valve (19) is greater than the outlet pressure of the carbon canister (8) and less than the absolute value of the negative pressure at the inlet of the throttle valve (18).

7. The fuel evaporation control system according to claim 3, characterized in that, All the sealing elements (98) are rubber rings.

8. The fuel evaporation control system according to any one of claims 1-6, characterized in that, Both the first connecting pipe (2) and the second connecting pipe (3) are metal pipes, and both the first connecting pipe (2) and the second connecting pipe (3) are welded together with the fuel tank (1).

9. The fuel evaporation control system according to any one of claims 1-6, characterized in that, The elastic element (94) is a spring.

10. A fuel evaporation control method, applied to the fuel evaporation control system according to any one of claims 1-9, characterized in that, The fuel evaporation control method includes: Add fuel to the fuel tank (1), open the fuel tank cap (4), and let the elastic element (94) push the valve core assembly upward so that the first interface (92) is disconnected from the second interface (93). The air in the fuel tank (1) is discharged through the first connecting pipe (2), the first pipe (7), the fuel tank cap joint (5), the fourth pipe (12), the three-way pipe (13), the fifth pipe (14), the sixth pipe (15), and the carbon canister (8). Close the fuel tank cap (4) and push the valve core assembly down so that the first interface (92) and the second interface (93) are connected. The air in the fuel tank (1) is discharged through the second connecting pipe (3), the third pipe (11), the on / off valve (9), the second pipe (10), the fourth pipe (12), the three-way pipe (13), the fifth pipe (14), the sixth pipe (15) and the carbon canister (8).

11. The fuel evaporation control method according to claim 10, characterized in that, During the refueling process, fuel enters the fuel tank (1) through the fuel tank cap connector (5) and the fuel supply pipe (6). When the amount of fuel flowing into the inner cavity of the fuel tank (1) reaches the insertion port of the first connecting pipe (2), the insertion port of the first connecting pipe (2) is sealed by fuel to prevent air from flowing out of the inner cavity of the fuel tank (1). The area above the insertion port of the first connecting pipe (2) in the inner cavity of the fuel tank (1) is the remaining air, which is sealed in the upper part of the inner cavity of the fuel tank (1). Fuel continues to be added until the fuel fills the inner cavity of the fuel supply pipe (6).

12. The fuel evaporation control method according to claim 10, characterized in that, After the fuel tank cap (4) is closed, the air inside the fuel tank (1) is discharged through the second connecting pipe (3), the third pipe (11), the on / off valve (9), the second pipe (10), the fourth pipe (12), the three-way pipe (13), the fifth pipe (14), the sixth pipe (15) and the carbon canister (8), while the fuel inside the fuel delivery pipe (6) flows into the fuel tank (1) under the action of gravity.

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