Carbon-free tank type oil gas recovery system and vehicle

Abstract

The invention relates to the technical field of vehicles, and discloses a carbon-free tank type oil gas recovery system and a vehicle, the carbon-free tank type oil gas recovery system comprises a high-pressure fuel tank, the high-pressure fuel tank is used for storing fuel oil and sealing gasoline steam in the fuel tank; the condenser is connected with an internal gas chamber of the high-pressure fuel tank through a gas inlet pipe and is used for receiving and condensing fuel steam from the high-pressure fuel tank; the recovery pipeline is connected between the condenser and the high-pressure fuel tank and is used for guiding liquid fuel formed after condensation into the high-pressure fuel tank; the one-way valve is arranged on the recovery pipeline and is used for preventing the fuel steam from flowing back through the recovery pipeline; and the high-pressure fuel tank isolation valve is communicated to one end, close to the recovery pipeline, of the condenser, and is used for controlling the pressure release and sealing of the high-pressure fuel tank. Oil gas is recovered for the plug-in hybrid electric vehicle through the design of the carbon-free tank.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicles, in particular to a carbon-can-free oil vapor recovery system and vehicle. BACKGROUND

[0002] Traditional oil vapor recovery systems usually include a carbon can and other components for recovering and processing oil vapor generated by fuel evaporation. This traditional fuel evaporation relies on the intake negative pressure generated by the periodic operation of the engine to complete the desorption regeneration of the carbon can.

[0003] However, in a plug-in hybrid vehicle, the vehicle can run in pure electric mode for a long time, and the engine does not work during this period, interrupting this regeneration mechanism. The carbon can cannot complete the desorption regeneration process, and the carbon can fails due to adsorption saturation. The saturated carbon can not only loses the ability to process new fuel vapor, but also becomes a channel for oil vapor leakage, causing fuel evaporation pollutants to be directly discharged into the atmosphere, causing environmental pollution and fuel waste. SUMMARY

[0004] The purpose of the present application is to solve the problem that the carbon can cannot effectively recover and process fuel vapor in the oil vapor recovery system of a plug-in hybrid vehicle in the prior art.

[0005] To achieve the above purpose, the present application provides a carbon-can-free oil vapor recovery system, comprising: a high-pressure fuel tank for storing fuel and sealing gasoline vapor in the fuel tank; a condenser connected to the internal gas chamber of the high-pressure fuel tank through an intake pipe for receiving and condensing fuel vapor from the high-pressure fuel tank; a recovery pipeline connected between the condenser and the high-pressure fuel tank for guiding the liquid fuel formed after condensation into the high-pressure fuel tank; a one-way valve provided on the recovery pipeline for preventing fuel vapor from flowing back through the recovery pipeline; a high-pressure fuel tank isolation valve connected to one end of the condenser close to the recovery pipeline for controlling the pressure release and sealing of the high-pressure fuel tank.

[0006] The advantages of the carbon tank-free oil vapor recovery system over the prior art are that for plug-in hybrid vehicles that use pure electric mode for a long time, the oil vapor adsorbed by the carbon tank cannot be effectively desorbed from the carbon tank by using the negative pressure generated when the engine is working, resulting in that the oil vapor recovery system cannot continue to recover fuel vapor and may even cause oil vapor leakage. The carbon tank-free oil vapor recovery system of the present application cancels the carbon tank and its related accessories, directly uses the condenser to condense the fuel vapor into liquid fuel and then guide it back into the high-pressure fuel tank, effectively solves the problem of saturated adsorption of oil vapor in the carbon tank and inability to desorb oil vapor in time, and reduces the complexity of the oil vapor recovery system, further saving costs.

[0007] In some embodiments, the condenser comprises a micro-channel heat exchange structure arranged inside the condenser for increasing the fuel vapor heat exchange area.

[0008] In some embodiments, a roll-over valve and a refueling oil quantity control valve are further included, the roll-over valve is communicated with the refueling oil quantity control valve through an air venting pipeline, and the refueling oil quantity control valve is communicated to the air inlet pipe for guiding the fuel vapor in the high-pressure fuel tank to the condenser.

[0009] In some embodiments, the condenser cools the fuel vapor by connecting the refrigeration pipeline of the vehicle air conditioner to the condensing flow channel of the micro-channel heat exchange structure.

[0010] In some embodiments, the condenser is located at the top of the high-pressure fuel tank and is arranged in a spaced manner with the top of the high-pressure fuel tank.

[0011] In some embodiments, a fuel refueling pipe is arranged on the side of the high-pressure fuel tank, and a tank cover is arranged at the free end of the fuel refueling pipe; a refueling one-way valve is arranged in the high-pressure fuel tank, and the refueling one-way valve is communicated with the fuel refueling pipe.

[0012] In some embodiments, a gas return pipe is further included, one end of the gas return pipe is communicated to the end of the fuel refueling pipe close to the tank cover, and the other end of the gas return pipe is communicated to the end of the condenser close to the air inlet pipe.

[0013] In some embodiments, a pressure sensor is further included, the pressure sensor is arranged in the high-pressure fuel tank and is used for detecting the airtightness of the high-pressure fuel tank.

[0014] In some embodiments, an exhaust pipeline is further included, the exhaust pipeline is communicated to the air outlet of the condenser and is used for exhausting air; wherein the high-pressure fuel tank isolation valve is arranged on the exhaust pipeline and is arranged in a spaced manner with the air outlet of the condenser.

[0015] The application further provides a vehicle comprising the carbon-can-free oil gas recovery system as described above.

[0016] The vehicle has the same advantages as the carbon-can-free oil gas recovery system described above relative to the prior art, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0017] The above and / or additional aspects and advantages of the application will become apparent and be readily appreciated from the description of the embodiments, given in conjunction with the accompanying drawings in which: Figure 1 FIG. 1 is a structural schematic diagram of a carbon-can-free oil gas recovery system according to an embodiment of the application.

[0018] Reference signs: 1, ash filter; 2, exhaust pipeline; 3, high-pressure fuel tank isolation valve; 4, condenser; 5, fuel filling pipe; 6, tank cover; 7, high-pressure fuel tank; 8, fuel pump; 9, pressure sensor; 10, one-way valve; 11, roll-over valve; 12, breather pipeline; 13, fuel filling quantity control valve; 14, float-type fuel quantity sensor; 15, fuel filling one-way valve; 16, return gas pipe; 17, recovery pipeline; 18, air inlet pipe. DETAILED DESCRIPTION

[0019] In order to make the above objectives, features and advantages of the application more apparent, specific embodiments of the application are described in detail below in conjunction with the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the application. However, the application can be practiced in a variety of ways other than those described herein, and skilled artisans can make similar improvements without departing from the spirit of the application, so the application is not limited to the specific embodiments disclosed below.

[0020] In the description of the application, it should be understood that the terms "center", "length", "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0021] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0022] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0023] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0024] In the related technologies of plug-in hybrid electric vehicle oil and gas recovery systems, the charcoal canister is the core component of the entire oil and gas recovery process.

[0025] The basic working principle of a charcoal canister is a cycle of adsorption, collection, desorption, and regeneration of fuel vapor. The canister is filled with high-performance activated carbon, which adsorbs and collects fuel vapor from the fuel tank, preventing it from being directly released into the atmosphere and causing pollution. To recover and reuse the fuel vapor in the canister and ensure its continuous adsorption capacity, the canister works in concert with a solenoid valve, desorption lines, and the negative pressure in the intake manifold during engine operation to desorb the fuel vapor. When the engine is running, a negative pressure is generated in the intake manifold; the electronic control unit opens the solenoid valve in a timely manner. Under the action of the pressure difference, the fuel vapor adsorbed in the pores of the activated carbon in the canister is drawn out of the canister and enters the engine intake manifold, ultimately entering the cylinder to participate in combustion.

[0026] Since the desorption of fuel vapors depends entirely on the operation of the engine, but the engine of a plug-in hybrid vehicle does not work during long-term pure electric driving, it cannot provide the negative pressure in the intake manifold necessary for desorption. This results in the inability to desorb and utilize the fuel vapors in the charcoal canister. At the same time, the charcoal canister, solenoid valve, adsorption and desorption pipelines on which fuel vapors desorption depend also bring problems of high system complexity, complicated calibration and high cost. Challenges also exist in terms of vehicle layout, durability and maintenance, affecting the economy and reliability of the vehicle.

[0027] This application provides a carbon-free tank-type oil and gas recovery system and vehicle.

[0028] The vehicle described in this application includes the aforementioned carbon-free canister-type oil and gas recovery system.

[0029] Please refer to Figure 1 The carbon-free tank-type fuel vapor recovery system of this application includes a high-pressure fuel tank 7, a condenser 4, a recovery pipeline 17, a one-way valve 10, and a high-pressure fuel tank isolation valve 3. The high-pressure fuel tank 7 stores fuel and seals gasoline vapor within the tank. The condenser 4 is connected to the internal gas chamber of the high-pressure fuel tank 7 via an intake pipe 18, and receives and condenses fuel vapor from the high-pressure fuel tank 7. The recovery pipeline 17 connects the condenser 4 and the high-pressure fuel tank 7, and guides the condensed liquid fuel into the high-pressure fuel tank 7. The one-way valve 10 is located on the recovery pipeline 17 to prevent backflow of fuel vapor through the recovery pipeline 17. The high-pressure fuel tank isolation valve 3 is connected to the end of the condenser 4 near the recovery pipeline 17, and controls the pressure release and sealing of the high-pressure fuel tank 7.

[0030] The upper part of the high-pressure fuel tank 7 has a gas chamber to contain fuel vapors that are produced during refueling or fuel vapors formed by the evaporation of liquid fuel stored in the high-pressure fuel tank 7. The high-pressure fuel tank 7 maintains a high degree of airtightness during daily storage and vehicle operation, effectively sealing the fuel vapors and preventing fuel vapor leakage that could pollute the environment.

[0031] The condenser 4 has an air inlet at one end and a liquid outlet at the other end. The high-pressure fuel tank 7 has an air outlet and a return outlet at both ends, which are connected through a gas chamber inside the high-pressure fuel tank 7. The air inlet of the condenser 4 is connected to the air outlet of the high-pressure fuel tank 7 via an air inlet pipe 18, allowing fuel vapor in the high-pressure fuel tank 7 to be transported from the top of the high-pressure fuel tank 7 to the condenser 4. The condenser 4 has a heat exchange channel inside. The fuel vapor flowing through the heat exchange channel of the condenser 4 is cooled by heat exchange with a cooling medium, causing the gaseous fuel vapor to undergo a phase change, condensing from a gaseous state back into liquid fuel.

[0032] The recovery pipeline 17 is connected between the liquid outlet of the condenser 4 and the return port of the high-pressure fuel tank 7. The high-pressure fuel tank 7, the intake pipe 18, the condenser 4 and the recovery pipeline 17 together form a closed return loop, which allows the fuel vapor to flow a sufficiently long distance through the complete heat exchange path inside the condenser 4 and be fully cooled. Then, the liquid fuel formed after condensation inside the condenser 4 is guided back to the high-pressure fuel tank 7 by gravity or pressure difference, thus realizing closed-loop fuel recovery.

[0033] A one-way valve 10 is installed on the recovery line 17. The opening direction of the one-way valve 10 is set to allow only the condensed liquid fuel to flow from the condenser 4 to the high-pressure fuel tank 7, while not allowing the gaseous fuel vapor in the high-pressure fuel tank 7 to enter the condenser 4 through the recovery line 17, thereby maintaining the stability of the overall flow direction of fuel vapor in the oil and gas recovery system.

[0034] Because one end of the high-pressure fuel tank isolation valve 3 is connected to the end of the condenser 4 near the recovery pipe 17, and the other end is open to the atmosphere, the high-pressure fuel tank isolation valve 3 acts as a switch to control the switching between closed and open states of the aforementioned return loop, controlling the pressure release and sealing of the entire vapor recovery system. When the pressure in the system exceeds a preset safety threshold, the high-pressure fuel tank isolation valve 3 is opened in a controlled manner to release the excessive pressure. When the pressure returns to normal, the high-pressure fuel tank isolation valve 3 closes, restoring the system to a sealed state.

[0035] Please refer to Figure 1 In some embodiments, the condenser 4 includes a microchannel heat exchange structure located inside the condenser 4 to increase the heat exchange area of ​​fuel vapor.

[0036] Multiple sets of this microchannel heat exchange structure can be arranged along the length of the condenser 4 body. Taking one set as an example, it contains multiple interconnected thin tubes, forming condensation channels. The air conditioning refrigeration lines can be connected to the condensation channels to cool the fuel vapor. Specifically, the air conditioning refrigeration lines are connected to the thin tubes in the microchannel heat exchange structure, allowing refrigerant to flow into each condensation channel, thereby cooling the fuel vapor in the condenser 4. During operation, the fuel vapor introduced from the intake pipe 18 is distributed to the fuel vapor channels of the condenser 4. Due to the large specific surface area and small hydraulic diameter of the thin tubes, the contact area between the fuel vapor and the condensation channel wall is increased, enabling efficient heat exchange in the condenser 4. At the same time, the parallel arrangement of the thin tubes also divides the fuel vapor into thin laminar flows that pass through the outer sides of the thin tube structure, making it easier for the fuel vapor to be cooled to its condensation point, thereby further improving the condensation efficiency. This microchannel heat exchange structure is simple in structure and low in cost. It not only significantly improves the condensation efficiency per unit volume by increasing the heat exchange area, making the condenser 4 structure more compact, but also promotes the laminar flow of fuel vapor. The improved condensation efficiency also shortens the residence time of fuel vapor in the condenser 4, thereby reducing the resistance of fuel vapor flow in the return loop and thus avoiding affecting the smoothness of fuel filling.

[0037] Please refer to Figure 1 In some implementations, the condenser 4 cools fuel vapor by connecting the vehicle air conditioning cooling pipes to the condensation channel of the microchannel heat exchange structure.

[0038] Condenser 4 uses the air conditioning's refrigerant piping as a cooling source for condensing fuel vapors. Condenser 4 integrates fuel vapor and condensation channels, which are connected via piping to the vehicle's air conditioning system compressor, condenser 4, expansion valve, and other components, forming a complete refrigeration cycle. During vehicle operation, the high-temperature, high-pressure liquid refrigerant output from the vehicle's air conditioning compressor, after passing through the expansion valve, has a portion of its low-temperature, low-pressure refrigerant diverted to the condensation channel of condenser 4. When fuel vapor flows through adjacent fuel vapor channels within condenser 4, the refrigerant absorbs a large amount of heat through evaporation, causing a rapid decrease in the wall temperature of the fuel vapor channel. The fuel vapor rapidly releases heat and condenses into liquid fuel upon contact with the low-temperature wall. This fully utilizes the vehicle's air conditioning system, providing a stable and efficient active cooling source for fuel vapor condensation, unaffected by engine operating conditions, while still allowing operation during pure electric driving in plug-in hybrid vehicles.

[0039] Please refer to Figure 1 In some embodiments, the vapor recovery system also includes a tipper valve 11 and a fuel filling control valve 13. The tipper valve 11 is connected to the fuel filling control valve 13 via a vent pipe 12. The fuel filling control valve 13 is connected to the intake pipe 18 and is used to guide the fuel vapor in the high-pressure fuel tank 7 to the condenser 4.

[0040] Because the rollover valve 11 is fixedly installed at the top inside the high-pressure fuel tank 7, located in the gas chamber of the high-pressure fuel tank 7, it can maintain the internal pressure of the high-pressure fuel tank 7 at a certain value. Under normal conditions or when the internal pressure of the high-pressure fuel tank 7 is too high, the rollover valve 11 remains open, allowing fuel vapor to enter the condenser 4 through the vent pipe 12 and the fuel filler quantity control valve 13. When the internal pressure of the high-pressure fuel tank 7 is too low while the vehicle is running at high speed, the rollover valve 11 closes, preventing the fuel tank from collapsing. In addition, in the event of extreme vehicle tilting or rollover accidents, the rollover valve 11 closes internally, thereby cutting off the venting path and preventing fuel leakage.

[0041] The inlet of the fuel quantity control valve 13 is connected to the outlet of the tipper valve 11 via a vent pipe 12. The fuel quantity control valve 13 is fixedly installed at the top inside the high-pressure fuel tank 7, and its outlet is connected to the air inlet of the intake pipe 18. Since the fuel quantity control valve 13 is a normally open valve, during normal vehicle operation, fuel vapor generated in the high-pressure fuel tank 7 can flow sequentially through the open tipper valve 11, the vent pipe 12, and the fuel quantity control valve 13, ultimately flowing into the intake pipe 18 and being guided to the condenser 4 for condensation. This fuel vapor flow path is the normal fuel vapor recovery path. During refueling, when the fuel level rises to the preset level, the float mechanism of the fuel quantity control valve 13 rises under the buoyancy of the fuel, at which point its internal valve port closes, triggering automatic shut-off and achieving precise control of the refueling amount. At this time, the closing of the fuel quantity control valve 13 also simultaneously cuts off the connection between the high-pressure fuel tank 7 and the intake pipe 18 through the aforementioned fuel vapor recovery path, thereby regulating the amount of fuel vapor passing through.

[0042] The vent pipe 12, which connects the rollover valve 11 and the fuel filling control valve 13, is spaced apart from the inner top wall of the high-pressure fuel tank 7. This creates a gap between the outer wall of the vent pipe 12 and the inner top wall of the fuel tank, thus reducing the influence of the pipe on the flow of fuel vapor in the gas chamber. It also prevents the sloshing fuel from accumulating between the vent pipe 12 and the inner top of the fuel tank when the vehicle is driving, braking, or tilting.

[0043] In one example, a fuel pump 8 is installed in the high-pressure fuel tank 7 of a plug-in hybrid vehicle to deliver fuel from the high-pressure fuel tank 7 to the engine. A float-type fuel level sensor 14 can be integrated on the fuel pump 8. The float on the float-type fuel level sensor 14 drives the float rod to move, thereby causing a change in the resistance on the float-type fuel level sensor 14 and outputting a resistance value. After being calculated by the vehicle's electronic control unit (ECU), it is converted into fuel level information displayed on the vehicle's instrument panel.

[0044] Please refer to Figure 1 In some embodiments, the condenser 4 is located on top of the high-pressure fuel tank 7 and is spaced apart from the top of the high-pressure fuel tank 7.

[0045] The condenser 4 is fixed to the top of the high-pressure fuel tank 7 by a bracket. This optimized layout utilizes the unused space above the high-pressure fuel tank 7 to install the condenser 4, making the overall vehicle layout more compact. At the same time, a certain gap is maintained between the bottom surface of the condenser 4 and the top outer surface of the high-pressure fuel tank 7, providing the necessary space for installing the intake pipe 18, the recovery pipe 17, and the one-way valve 10. This gap also forms an airflow channel; when the vehicle is in motion, air flows through this gap and uses the running air to assist in cooling the condenser 4 and the high-pressure fuel tank 7. Furthermore, the existence of the gap effectively reduces the impact of the high-pressure fuel tank 7, as the main heat source, on the performance of the condenser 4, ensuring the stability of the low-temperature heat exchange environment of the condenser 4.

[0046] The intake pipe 18 and the recovery pipe 17 are located between the condenser 4 and the high-pressure fuel tank 7, and both are vertically arranged vertically. This ensures that fuel vapor and fuel flow smoothly in the intake pipe 18 and the recovery pipe 17, respectively. The intake pipe 18 and the recovery pipe 17 are located at opposite ends of the condenser 4, allowing the fuel vapor entering the condenser 4 to condense fully. The end of the recovery pipe 17 closest to the high-pressure fuel tank 7 is connected to the middle of the high-pressure fuel tank 7 along its length. This facilitates the smooth flow of fuel from the recovery pipe 17 into the liquid fuel at the bottom of the tank, preventing violent impact or bubble formation on the liquid surface. The one-way valve 10, located in the recovery pipe 17, has its bottom positioned higher than the inner top wall of the high-pressure fuel tank 7 to prevent fuel stagnation at the valve body. This ensures that the condensed liquid fuel can completely flow back into the high-pressure fuel tank 7 under gravity, preventing the retention of stale fuel.

[0047] For the intake pipe 18, recovery pipe 17 and one-way valve 10 installed between the condenser 4 and the high-pressure fuel tank 7, the intake pipe 18 is connected upward from the top of the high-pressure fuel tank 7 to the intake port of the condenser 4, and the recovery pipe 17 is connected downward from the liquid outlet of the condenser 4 to the high-pressure fuel tank 7. This arrangement not only minimizes the pipe path, but also ensures the smooth upward flow of fuel vapor. The condensed liquid fuel can also flow back to the high-pressure fuel tank 7 naturally along the recovery pipe 17 under the action of gravity, thereby improving the reliability of the return flow.

[0048] Please refer to Figure 1 In some embodiments, a fuel filling pipe 5 is connected to the side of the high-pressure fuel tank 7, and a tank cover 6 is provided at the free end of the fuel filling pipe 5; a fuel filling check valve 15 is provided inside the high-pressure fuel tank 7, and the fuel filling check valve 15 is connected to the fuel filling pipe 5.

[0049] One end of the fuel filling pipe 5 is welded and connected to the side of the high-pressure fuel tank 7. The other end of the fuel filling pipe 5 is away from the high-pressure fuel tank 7, i.e., the free end, and extends into the fuel filler door on the side of the vehicle body. An openable and sealable tank cover 6 is provided at the free end to seal the fuel filling pipe 5 when the vehicle does not need to be refueled, so as to isolate it from the outside world and prevent fuel vapor from escaping.

[0050] A one-way fuel filler valve 15 is fixedly installed on the inner wall of the high-pressure fuel tank 7 and is connected in one direction to the fuel filler pipe 5. The one-way fuel filler valve 15 only allows fuel to flow from the fuel filler pipe 5 into the high-pressure fuel tank 7, preventing fuel from flowing back from the high-pressure fuel tank 7 into the fuel filler pipe 5. In one example, the one-way fuel filler valve 15 can adopt a float type or a duckbill type structure. Specifically, when the vehicle is in normal driving and fuel storage state, the one-way fuel filler valve 15 remains closed under the action of its own weight, spring force, or fuel vapor pressure in the fuel tank. This closed state can effectively prevent liquid fuel inside the high-pressure fuel tank 7 from flowing back into the fuel filler pipe 5 due to vehicle bumps and shaking, and also prevent fuel vapor from escaping through the fuel filler pipe 5. When refueling, the fuel nozzle is opened and inserted into the tank cap 6, and fuel is injected from the fuel filler pipe 5 at a certain pressure and flow rate, which allows the fuel to open the one-way fuel filler valve 15, thus allowing fuel to be smoothly injected into the high-pressure fuel tank 7. Once refueling is completed, the one-way fuel filler valve 15 will immediately close automatically under the action of the reset force.

[0051] Please refer to Figure 1 In some embodiments, the vapor recovery system also includes a return pipe 16, one end of which is connected to the fuel filling pipe 5 near the tank cap 6, and the other end is connected to the condenser 4 near the intake pipe 18.

[0052] One end of the return vent pipe 16 is connected to the end of the fuel filler pipe 5 near the tank cap 6, which is the location where fuel vapor is most likely to collect and overflow during refueling. The other end is connected to the end of the condenser 4 near the intake pipe 18. In one example, the end of the return vent pipe 16 connected to the condenser 4 is located in the lower middle part of the end face of the condenser 4. This allows the fuel vapor entering the condenser 4 directly from the return vent pipe 16 to flow upward against gravity through most of the condensation path inside the condenser 4 after entering from the lower middle part of the condenser 4. This prolongs the residence time of the fuel vapor in the condenser 4 and ensures that the fuel vapor can fully contact the cooling wall surface, improving condensation efficiency. The return vent pipe 16 connecting the fuel filler pipe 5 and the condenser 4 forms a branch channel for fuel vapor recovery. Specifically, during refueling, a large amount of fuel vapor generated by the refueling impact accumulates near the filler neck of the fuel filler pipe 5. This fuel vapor preferentially passes through the shorter and less resistant vapor recovery branch channel and is directly guided to the condenser 4 via the return vent pipe 16 for condensation and recovery. This effectively prevents fuel vapor from escaping back from the open filler neck during refueling, improving the vapor recovery rate and reducing environmental pollution. Simultaneously, the high-speed fuel flow during refueling compresses the air and fuel vapor at the bottom of the fuel filler pipe 5, creating a cavity mixed with air and fuel vapor in the fuel flow. This results in greater refueling resistance, and may even cause fuel backflow or nozzle disconnection. The return vent pipe 16 connects the balance condenser 4 and the fuel filler pipe 5, balancing the pressure difference between them, thus ensuring smooth fuel flow into the high-pressure fuel tank 7.

[0053] Please refer to Figure 1 In some embodiments, the oil and gas recovery system also includes a pressure sensor 9, which is installed inside the high-pressure fuel tank 7 to detect the airtightness of the high-pressure fuel tank 7.

[0054] Pressure sensor 9 is fixedly installed on the top surface inside the high-pressure fuel tank 7 to continuously monitor the fuel vapor pressure in the gas chamber of the high-pressure fuel tank 7, thereby determining the integrity of the entire vapor recovery system's airtightness. Pressure sensor 9 is connected to the vehicle's ECU signal. When the vehicle engine is not running for an extended period and the condenser 4 is not operating, the vapor recovery system should be in a stable, airtight state. The ECU obtains the initial pressure of the high-pressure fuel tank 7 through pressure sensor 9 and continuously monitors pressure changes over a subsequent period. Simultaneously, the detection data from pressure sensor 9 is also used to coordinate the operation of the high-pressure fuel tank isolation valve 3 and the rollover valve 11. When pressure sensor 9 detects that the pressure inside the high-pressure fuel tank 7 exceeds the set safety upper limit, the ECU instructs the high-pressure fuel tank isolation valve 3 to open and release pressure; when the pressure falls below the set lower limit, the ECU instructs the high-pressure fuel tank isolation valve 3 and even the rollover valve 11 to close, shutting off the vapor recovery system's connection to the outside atmosphere or even stopping the vapor recovery process, ensuring the pressure returns to the normal range. If there is a leak in the system, the pressure will drop abnormally; if excessive fuel evaporation occurs due to increased ambient temperature, the pressure will rise abnormally. Whether the pressure is below or above the reasonable pressure range, the ECU can determine that the sealing of the vapor recovery system is abnormal, thereby triggering the corresponding fault indicator light to alert the driver, and storing the fault code for subsequent maintenance personnel to perform maintenance and diagnosis.

[0055] Please refer to Figure 1 In some embodiments, the oil and gas recovery system further includes an exhaust pipe 2 connected to the outlet of the condenser 4, and a high-pressure fuel tank isolation valve 3 located away from the condenser 4 at one end for discharging air; wherein the high-pressure fuel tank isolation valve 3 is disposed on the exhaust pipe 2 and spaced apart from the outlet of the condenser 4.

[0056] The intake port of exhaust pipe 2 is sealed to the outlet end of high-pressure fuel tank isolation valve 3, that is, the end of high-pressure fuel tank isolation valve 3 away from condenser 4. The pipe body of exhaust pipe 2 is arranged along the wiring harness path of the whole vehicle, and the exhaust port of exhaust pipe 2 can be set at a specific location under the vehicle chassis. It can be selected in a place with good air circulation, away from heat sources and not easily invaded by water or pollutants, so as to complete the final air discharge and pressure release of the oil and gas recovery system.

[0057] The mixture of air and fuel vapor in condenser 4 is condensed and liquefied into liquid fuel, which is then returned to the high-pressure fuel tank 7. The air is then separated and discharged into the atmosphere through exhaust pipe 2. The specific principle is as follows: Inside condenser 4, the mixture of air and fuel vapor is cooled together. Since the condensation temperature of fuel vapor is much higher than that of air, when the temperature drops below the condensation temperature of fuel vapor but still much higher than the liquefaction temperature of air (-196°C), only the fuel vapor undergoes a phase change, condensing from a gaseous state into tiny liquid droplets, while the air remains gaseous. In one example, a dust filter 1 can be installed at the outlet of exhaust pipe 2 to filter out air that may enter exhaust pipe 2 in reverse, preventing dust and other impurities from entering the high-pressure fuel tank isolation valve 3 or condenser 4.

[0058] The carbon-canister-free vapor recovery system of this application meets the requirements of Type IV test (for fuel vapor evaporation pollutants) and Type VII test (for refueling process pollutants) in the "Limits and Measurement Methods for Pollutant Emissions from Light-Duty Vehicles (China VI)" (i.e., "National VI" standard). It not only solves the problem in related technologies where the carbon canister-type vapor recovery system of plug-in hybrid vehicles cannot desorb the vapors in the carbon canister when the engine is not working during long-term pure electric driving, thus improving the reliability of the vapor recovery system, but also further reduces the complexity of the vapor recovery system and saves costs.

[0059] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0060] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A carbon-free tank-type oil and gas recovery system, characterized in that, include: High-pressure fuel tank (7), the high-pressure fuel tank (7) is used to store fuel and seal gasoline vapor inside the fuel tank; The condenser (4) is connected to the internal gas chamber of the high-pressure fuel tank (7) via an air inlet pipe (18) and is used to receive and condense fuel vapor from the high-pressure fuel tank (7). Recovery pipeline (17) is connected between the condenser (4) and the high-pressure fuel tank (7) to guide the liquid fuel formed after condensation into the high-pressure fuel tank (7); A one-way valve (10) is provided on the recovery pipeline (17) to prevent fuel vapor from flowing back through the recovery pipeline (17); A high-pressure fuel tank isolation valve (3) is connected to one end of the condenser (4) near the recovery pipeline (17) and is used to control the pressure release and sealing of the high-pressure fuel tank (7).

2. The carbon-free tank-type oil and gas recovery system according to claim 1, characterized in that, The condenser (4) includes a microchannel heat exchange structure, which is located inside the condenser (4) to increase the heat exchange area of ​​fuel vapor.

3. The carbon-free tank-type oil and gas recovery system according to claim 1, characterized in that, It also includes a tipper valve (11) and a fuel quantity control valve (13). The tipper valve (11) is connected to the fuel quantity control valve (13) through a vent pipe (12). The fuel quantity control valve (13) is connected to the air intake pipe (18) and is used to guide the fuel vapor in the high-pressure fuel tank (7) to the condenser (4).

4. The carbon-free tank-type oil and gas recovery system according to claim 2, characterized in that, The condenser (4) cools fuel vapor by connecting the vehicle air conditioning cooling pipes to the condensation channel of the microchannel heat exchange structure.

5. The carbon-free tank-type oil and gas recovery system according to claim 1, characterized in that, The condenser (4) is located on top of the high-pressure fuel tank (7) and is spaced apart from the top of the high-pressure fuel tank (7).

6. The carbon-free tank-type oil and gas recovery system according to claim 1, characterized in that, The high-pressure fuel tank (7) is connected to a fuel filling pipe (5) on its side, and a tank cover (6) is provided at the free end of the fuel filling pipe (5). The high-pressure fuel tank (7) is equipped with a refueling check valve (15), which is connected to the fuel refueling pipe (5).

7. The carbon-free tank-type oil and gas recovery system according to claim 6, characterized in that, It also includes a return pipe (16), one end of which is connected to the fuel filling pipe (5) near the end of the tank cover (6), and the other end is connected to the condenser (4) near the end of the intake pipe (18).

8. The carbon-free tank-type oil and gas recovery system according to claim 1, characterized in that, It also includes a pressure sensor (9), which is disposed inside the high-pressure fuel tank (7) and is used to detect the airtightness of the high-pressure fuel tank (7).

9. The carbon-free tank-type oil and gas recovery system according to claim 1, characterized in that, It also includes an exhaust pipe (2), which is connected to the outlet of the condenser (4) for discharging air; The high-pressure fuel tank isolation valve (3) is installed on the exhaust pipe (2) and is spaced apart from the outlet of the condenser (4).

10. A vehicle, characterized in that, The carbon-free tank-type oil and gas recovery system includes any one of claims 1-9.

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