Device and method for measuring discharge amount of fuel steam in vehicle refueling process

Abstract

The invention discloses a device and method for measuring the discharge amount of fuel steam in the vehicle refueling process, and the device comprises a sealed collection device which is connected with a carbon tank emptying valve through a first communication pipeline and is connected with a fuel tank opening through a second communication pipeline; and the gas measuring device is connected with the closed collecting device and is used for detecting the content of the fuel steam collected by the closed collecting device. The measuring device is simple in structure, easy and convenient to operate and beneficial to popularization and promotion.

Description

Technical Field

[0001] This application generally relates to the field of motor vehicle emissions testing technology. More specifically, this application relates to a device for measuring fuel vapor emissions during vehicle refueling. Furthermore, this application also relates to a method for measuring fuel vapor emissions during vehicle refueling using the device. Background Art

[0002] With the continuous growth of the number of cars on the road, motor vehicle emission control is crucial to improving the quality of the atmospheric environment. Gasoline vehicles produce a large amount of fuel vapor during the refueling process. The volatile organic compounds such as benzene contained in them not only aggravate ozone and PM2.5 pollution, but also have carcinogenic risks, posing a significant threat to the ecological environment and public health. For this reason, the "Emission Standards for Air Pollutants from Gas Stations" (GB 20952-2020) mandate the control of oil and gas emissions during the refueling process. The current commonly used solution for collecting oil and gas during the refueling process is to integrate a sensing port, an oil and gas recovery hole, and a splash protector module at the front end of the refueling gun, and use a vacuum pump to recover the fuel vapor overflowing from the tank to the oil storage tank, thereby reducing escape. However, the existing evaporative emission measurement equipment is expensive to purchase and maintain, and requires frequent calibration, which severely restricts the large-scale application of this technology.

[0003] Therefore, there is an urgent need to develop a low-cost, easy-to-operate device or method for measuring evaporative emissions during vehicle refueling. Summary of the Invention

[0004] In order to at least solve one or more of the technical problems mentioned above, the present application proposes a device and method for measuring the emission of fuel vapor during vehicle refueling in multiple aspects. The measuring device is low-cost and the processing method is easy to operate.

[0005] In a first aspect, the present application provides a device for measuring the emission of fuel vapor during the refueling process of a vehicle, comprising: a closed collection device connected to a carbon canister vent valve via a first connecting line and connected to a fuel tank port via a second connecting line; and a gas measuring device connected to the closed collection device for detecting the content of fuel vapor collected by the closed collection device.

[0006] In some embodiments, a vacuum pump is integrated inside the closed collection device, and the vacuum degree of the vacuum pump is lower than the oil and gas recovery vacuum degree of the refueling gun.

[0007] In some embodiments, a pressure sensor and a temperature sensor are integrated inside the closed collection device.

[0008] In some embodiments, the closed collection device also includes an isolation valve, which is arranged on the connecting pipeline between the carbon canister and the fuel tank; the closed collection device is configured to have two working modes: a first mode: when the isolation valve is disconnected, only the fuel vapor in the carbon canister is collected; a second mode: when the isolation valve is turned on, the fuel vapor in the fuel tank and the carbon canister is collected at the same time.

[0009] In some embodiments, the gas measurement device is a flame ionization detector (FID), which can measure the total mass of hydrocarbons in the closed collection device.

[0010] In a second aspect, the present application provides a method for measuring the emission of fuel vapor during a vehicle refueling process using the above-mentioned measuring device, comprising the following steps: Step S1: in a non-refueling state, collecting the fuel vapor in the carbon canister as a background value; Step S2: in a refueling state, simultaneously collecting the fuel vapor content in the fuel tank and the carbon canister as a total evaporation amount; Step S3: calculating the difference between the total evaporation amount and the background value, and using the difference as the emission of fuel vapor during the refueling process.

[0011] In some embodiments, before executing step S1 , step S0 needs to be executed: simulating normal refueling conditions, measuring the exhaust flow rate after the carbon canister vent valve, and recording the reference flow value Q after the flow rate stabilizes.

[0012] In some embodiments, step S1 includes: step S11: opening the fuel tank cap, introducing gas into the fuel tank, and adjusting the gas input rate so that the exhaust flow rate after the carbon canister vent valve is equal to the reference flow value Q; step S12: collecting the fuel vapor in the carbon canister through the closed collection device; step S13: using a gas measuring device to measure the hydrocarbon content in the closed collection device, calculating the fuel vapor content based on the hydrocarbon content, and using the obtained fuel vapor content as the background value.

[0013] In some embodiments, step S2 includes: step S21: controlling the vacuum degree and refueling rate of the collection device to be the same as the vacuum degree and refueling rate of step S1, and using the closed collection device to collect fuel vapor in the fuel tank and carbon canister; step S22: using a gas measuring device to measure the hydrocarbon content in the closed collection device, calculating the fuel vapor content based on the hydrocarbon content, and using the obtained fuel vapor content as the total evaporation amount.

[0014] In some embodiments, the collection time of step S1 and step S2 is equal, and both are equal to the time required to fill the fuel tank.

[0015] By using the device for measuring the amount of fuel vapor emitted during a vehicle refueling process as provided above, the embodiment of the present application sets up a sealed collection device connected to the carbon canister and the fuel tank port to collect the fuel vapor during the refueling process, and then uses a gas measuring device to measure the content of the collected fuel vapor to obtain the amount of fuel vapor emitted during the vehicle refueling process. This solution has a simple structure and is easy to operate. Furthermore, in some embodiments, by setting an isolation valve on the connecting pipe between the carbon canister and the fuel tank, the sealed collection device can collect only the fuel vapor in the carbon canister as a background value, and then the total fuel vapor measured during the refueling process is subtracted from the background value to obtain the actual fuel vapor content during the refueling process, thereby making the obtained fuel vapor content more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other objects, features and advantages of the exemplary embodiments of the present application will become readily understood by reading the detailed description below with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present application are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0017] Figure 1 The device for measuring the emission of fuel vapor during vehicle refueling in an embodiment of the present application is shown;

[0018] Figure 2 The method for measuring the emission of fuel vapor during vehicle refueling in an embodiment of the present application is shown;

[0019] Figure 3 The method for measuring the emission of fuel vapor during vehicle refueling in an embodiment of the present application is shown;

[0020] Figure 4 A method for measuring the emission of fuel vapor during vehicle refueling in an embodiment of the present application is shown.

[0021] In the figure: 100, a device for measuring the emission of fuel vapor during the refueling process of a vehicle;

[0022] 101. Sealed collection device; 102. Gas measuring device; 103. Carbon canister; 104. First connecting pipeline; 105. Second connecting pipeline; 106. Fuel gun; 107. Fuel tank port; 108. Fueling pipeline; 109. Oil and gas return pipeline; 110. Fuel tank; 111. Isolation valve. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0024] It should be understood that the terms "include" and "comprising" used in the description and claims of this application indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0025] It should also be understood that the terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit this application. As used in this specification and claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It should also be further understood that the term "and / or" as used in this specification and claims refers to any and all possible combinations of one or more of the associated listed items, including and including these combinations.

[0026] As used in this specification and claims, the term "if" can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0027] The specific implementation of the present application will be described in detail below with reference to the accompanying drawings.

[0028] like Figure 1 As shown, in some embodiments, the present application provides a device 100 for measuring the emission of fuel vapor during the refueling process of a vehicle, including: a closed collection device 101, which is connected to the vent valve of the carbon canister 103 through a first connecting line 104, and is connected to the fuel tank port 107 through a second connecting line 105; and a gas measuring device 102, which is connected to the closed collection device 101 and is used to detect the fuel vapor content collected by the closed collection device 101.

[0029] In this embodiment, the device 100 for measuring the emission of fuel vapor during vehicle refueling (hereinafter referred to as the measuring device) includes a closed collection device 101 and a gas measuring device 102. Specifically, the closed collection device 101, as the core component of the entire measuring device, is detachably connected to the outlet of the vent valve on the carbon canister 103 through a first connecting line 104 to collect the fuel vapor in the carbon canister 103. At the same time, it is detachably connected to the fuel tank port 107 through a second connecting line 105 to collect the fuel vapor emitted from the fuel tank 110 during the refueling process. In addition, the gas measuring device 102 in this embodiment is connected to the closed collection device 101 and is mainly used to detect the content of fuel vapor collected by the closed collection device 101.

[0030] It is worth noting that the measuring device in this solution is usually made of high-strength, corrosion-resistant materials, so that it can work stably and reliably in a complex refueling environment, ensuring the accuracy of the measurement results.

[0031] When using the measuring device, first, the closed collection device 101 needs to be connected to the vehicle to be refueled through the first connecting line 104 and the second connecting line 105, and ensure that the connection is tight and leak-free. When the vehicle starts to refuel, the carbon canister 103 and the fuel vapor in the fuel tank will enter the closed collection device 101 through the first connecting line 104 and the second connecting line 105 under the action of oil and gas pressure and other factors and be effectively collected. During the collection process, the sealing and stability of the entire system must be ensured to prevent the mixing of external air or the escape of oil and gas from affecting the measurement results. After refueling is completed, the gas measuring device 102 is used to accurately measure the fuel vapor content in the closed collection device 101, and then the total fuel vapor emissions of the vehicle during the refueling process are calculated.

[0032] This solution simultaneously collects fuel vapor from both the fuel tank 110 and the carbon canister 103, enabling comprehensive and complete evaporative emissions data from the refueling process. This avoids the inaccurate data that can result from collecting fuel vapor from only a single location. Furthermore, the measurement device is relatively simple in structure, eliminating the need for large, specialized closed chambers or other complex testing equipment, significantly reducing equipment acquisition costs.

[0033] It's worth noting that the fuel tank in this embodiment is equipped with a pressure sensor that monitors internal tank pressure. This prevents excessively high or low tank pressure from negatively impacting the oil and vapor recovery system, ensuring stable operation. Furthermore, two pipelines connect the fuel tank to the tank port 107: a refueling line 108 and a return line 109. During refueling, a fuel nozzle 106 is inserted into the tank port 107 to add fuel.

[0034] It is also worth mentioning that in order to effectively collect oil and gas without affecting the normal refueling of the refueling gun 106, a detachable connecting tee can be connected at the refueling port. Specifically, when refueling, the fuel flows from the refueling gun 106 into the fuel tank through the oil inlet of the tee. At the same time, the oil and gas escaping from the fuel tank port 107 enters the second connecting pipe 105 through the oil and gas collection interface of the tee and is introduced into the closed collection device 101. The internal design of the tee is ingenious to ensure that the flow of oil and gas does not interfere with the flow of fuel. This solution is easy to install and disassemble, does not require large-scale modification of the fuel tank port 107, and does not affect the normal use of the refueling gun 106. At the same time, it can effectively collect the oil and gas escaping from the fuel tank 110, reduce oil and gas leakage, reduce environmental pollution, and improve the safety and environmental friendliness of the refueling process.

[0035] In a specific embodiment, a vacuum pump is integrated inside the closed collection device 101 , and the vacuum degree of the vacuum pump is lower than the oil and gas recovery vacuum degree of the refueling gun 106 .

[0036] During the vehicle refueling process, in order to effectively collect the emission of fuel vapor, this solution specifically integrates a vacuum pump inside the closed collection device 101 to provide key power support for collecting oil and gas. This design ensures that the fuel vapor in the fuel tank and carbon canister 103 can be smoothly sucked into the closed collection device 101, avoiding leakage or escape of oil and gas during the collection process, thereby achieving effective collection of fuel vapor during the refueling process. In addition, this solution also carefully sets the vacuum degree of the vacuum pump to be lower than the oil and gas recovery vacuum degree of the refueling gun 106, which not only allows the fuel vapor to be collected efficiently, but also avoids interference with the oil and gas recovery system of the refueling gun 106, ensuring the smoothness and efficiency of the entire refueling and fuel vapor collection process.

[0037] Those skilled in the art will appreciate that efficient collection of fuel vapor is crucial during vehicle refueling. Setting the vacuum pump's vacuum level too low will result in insufficient suction in the collection device, preventing timely and effective collection of fuel vapor. This can cause fuel vapor to accumulate within the device, increasing the risk of leakage and posing a safety hazard. Therefore, this solution sets the vacuum pump's vacuum level slightly lower than the fuel vapor recovery vacuum level of refueling nozzle 106. This ensures sufficient suction for the collection device without interfering with the fuel vapor recovery system of refueling nozzle 106.

[0038] In a specific embodiment, the closed collection device 101 is internally integrated with a pressure sensor and a temperature sensor.

[0039] In this solution, a pressure sensor and a temperature sensor are integrated inside the closed collection device 101, both of which are connected to the main control unit. The pressure sensor monitors the pressure value in the collection device in real time. The main control unit accurately adjusts the operating power of the vacuum pump based on the pressure data it transmits, ensuring that the vacuum pump maintains a vacuum slightly lower than the oil and gas recovery system of the oil gun 106. The temperature sensor monitors the gas temperature in the collection device in real time. The main control unit converts the collected gas volume to a standard state based on the ideal gas law (PV=nRT) and the temperature data transmitted by the temperature sensor, cleverly eliminating the fuel vapor volume measurement error caused by ambient temperature fluctuations and significantly improving the measurement accuracy. In addition, the temperature sensor also has an abnormal temperature rise detection function. Once an abnormal increase in gas temperature is detected, this abnormal signal is immediately transmitted to the main control unit, triggering the alarm mechanism and taking corresponding measures in a timely manner to strictly prevent the oil and gas from causing safety risks such as combustion and explosion due to local high temperature, and fully guaranteeing the safety of the entire measuring device and the refueling process.

[0040] In a specific embodiment, the closed collection device 101 also includes an isolation valve 111, which is arranged on the connecting pipeline between the carbon canister 103 and the fuel tank; the closed collection device 101 is configured to have two working modes: the first mode: when the isolation valve 111 is disconnected, only the fuel vapor in the carbon canister 103 is collected; the second mode: when the isolation valve 111 is turned on, the fuel vapor discharged from the fuel tank 110 and the carbon canister 103 is collected at the same time.

[0041] In this solution, the carbon canister 103 and the fuel tank are connected through a connecting pipe, and an isolation valve 111 is provided on the connecting pipe. The main function of the isolation valve 111 is to control the on-off connection between the carbon canister 103 and the fuel tank, so as to enable the closed collection device 101 to quickly switch between the two working modes. Specifically, in the first mode, the isolation valve 111 is in the disconnected state, and the passage for the oil and gas in the fuel tank to enter the carbon canister 103 is closed, and the oil and gas cannot be discharged into the carbon canister 103 from this passage. At this time, the closed collection device 101 only collects gas from the carbon canister 103. This mode is mainly used for background value determination. In this way, the basic data of oil and gas emissions without interference from refueling operations can be accurately obtained. These basic data provide an important reference basis for subsequent emission calculations, ensuring the accuracy and reliability of the measurement results. In the second mode, isolation valve 111 is open, and the connection line between carbon canister 103 and the fuel tank is open. Fuel vapor can be discharged from the fuel tank through carbon canister 103 and through fuel tank port 107, and collected by the sealed collection device. This mode is used to measure evaporative emissions during the actual refueling process.

[0042] During actual use, testers first used the device's first mode to measure background values. Specifically, at a normal refueling rate, the exhaust flow rate after the vent valve of the carbon canister 103 stabilized was recorded. Subsequently, the fuel tank cap was opened and the gas used for background testing was introduced, maintaining a constant exhaust flow rate after the vent valve of the carbon canister 103. Fuel vapor from the carbon canister was collected using the sealed collection device 101, with the collection time based on the time it took to fill the tank. The collected gas was used as the background value. The device then switched to the second mode, using the same refueling rate and collection device vacuum level. Fuel vapor from the fuel tank port 107 and the carbon canister 103 during refueling was collected, and this collected fuel vapor was used as the total evaporation value. Finally, the total hydrocarbon emissions from the collection device were measured using the gas measurement device 102. The background value was subtracted from the total evaporation value to obtain the precise evaporative emissions during the refueling process. This operational process is not only scientific and rigorous, but also efficient and practical, providing an innovative and reliable solution for measuring evaporative emissions during vehicle refueling.

[0043] By simultaneously collecting fuel and vapor emissions from two pathways, this solution comprehensively captures fuel and vapor leakage during refueling operations. This provides critical data for accurately evaluating a vehicle's refueling emissions performance and helps provide a deeper understanding of the vehicle's emission characteristics during actual refueling.

[0044] In a specific embodiment, the gas measurement device 102 is a flame ionization detector (FID), which can measure the total mass of hydrocarbons in the closed collection device 101 .

[0045] In this solution, the gas measurement device 102 is a flame ionization detector (FID), which is not only connected to the main control unit but also connected to the sealed collection device 101 via a guide tube. During operation, the sealed collection device 101 collects fuel vapor, which is then introduced into the FID's combustion chamber via a guide tube. Within the combustion chamber, ion current signals are generated. This signal is amplified by an amplifier and processed by a data acquisition system, ultimately converting it into the total mass of hydrocarbons. The FID transmits this total mass to the main control unit, which converts it into the total volume of fuel vapor using density conversion, molar mass conversion, or other conversion methods.

[0046] The measurement device of this solution features a simple structure, low cost, and easy operation. This not only reduces the equipment's purchase cost but also allows operators to use it proficiently without extensive training. Furthermore, because the sealed collection device 101 has two modes, switching between these modes during use effectively eliminates the effects of background values ​​and improves measurement accuracy.

[0047] like Figure 2As shown, in some embodiments, the present application provides a method for measuring the emission of fuel vapor during the refueling process of a vehicle using the above-mentioned measuring device, comprising the following steps: Step S1: In a non-refueling state, collecting the fuel vapor in the carbon canister 103 as a background value; Step S2: In a refueling state, simultaneously collecting the fuel vapor in the fuel tank 110 and the carbon canister 103 as a total evaporation amount; Step S3: Calculating the difference between the total evaporation amount and the background value, and using the difference as the emission of fuel vapor during the refueling process.

[0048] The above scheme introduces in detail a device 100 for measuring the emission of fuel vapor during the refueling process of a vehicle. This scheme will introduce a method for using the above measuring device to measure the emission of fuel vapor during the refueling process of a vehicle. Specifically, the measuring method of the measuring device described in this application mainly covers three key steps. Step S1 is to collect the background value, that is, when there is no refueling, the isolation valve 111 is disconnected, and the closed collection device 101 only collects the fuel vapor in the carbon canister 103. This operation can obtain the fuel vapor emission data without the interference of refueling, providing a reference for subsequent accurate calculations. Step S2 is executed during the refueling process. At this time, the isolation valve 111 is turned on, and the closed collection device 101 synchronously collects the gas released from the carbon canister 103 and the fuel tank port 107, comprehensively capturing the oil and gas emissions generated during the refueling operation to ensure data integrity. Step S3 is calculation. By subtracting the background value from the total evaporation amount, the fuel vapor emission during refueling is accurately obtained, effectively measuring the actual emission level of the vehicle in the refueling state.

[0049] This solution collects gas from the vent valve of carbon canister 103 during non-refueling as a background value, and simultaneously collects gas from both the fuel tank 110 and the vent valve of carbon canister 103 during refueling as the total evaporation value. The difference between the two values ​​is then calculated to determine the fuel vapor emissions during refueling. This measurement method effectively eliminates interference from background factors, ensuring that the measurement results more accurately reflect the actual fuel vapor emissions generated during refueling.

[0050] In a specific embodiment, before executing step S1, step S0 needs to be executed: simulating normal refueling conditions, measuring the exhaust flow rate after the vent valve of the carbon canister 103, and recording the reference flow value Q after the flow rate stabilizes.

[0051] In this solution, before executing step S1, step S0 must be performed first. This involves simulating normal refueling conditions, measuring the exhaust flow rate after the vent valve of the carbon canister 103, and recording a baseline flow rate value Q. Specifically, within an experimental environment, parameters such as the refueling rate, fuel temperature, ambient temperature, and atmospheric pressure are precisely controlled to simulate conditions highly consistent with actual refueling scenarios. This ensures that the measured baseline flow rate value Q truly reflects the exhaust flow from the vent valve of the carbon canister 103 during actual vehicle use. While the vehicle is under simulated refueling conditions, a professional flow measurement instrument is connected to the pipeline after the vent valve of the carbon canister 103 to monitor the exhaust flow in real time. Once the flow rate stabilizes, the flow rate data is continuously recorded for a period of time. Data processing software then performs averaging and filtering to eliminate random errors and interference factors, ultimately obtaining an accurate and stable baseline flow rate value Q. This baseline flow rate value Q is a key reference parameter throughout the measurement process, representing the flow rate level of the exhaust gas from the vent valve of the carbon canister 103 under normal conditions. It provides an important basis for subsequent background value measurements and accurate calculation of evaporative emissions during the refueling process.

[0052] like Figure 3 As shown, in a specific implementation scheme, step S1 includes: step S11: opening the fuel tank cap, introducing gas into the fuel tank, and adjusting the gas input rate so that the exhaust flow rate after the vent valve of the carbon canister 103 is equal to the reference flow value Q; step S12: collecting the fuel vapor in the carbon canister through the closed collection device 101; step S13: using a gas measuring device to measure the hydrocarbon content in the closed collection device, calculating the fuel vapor content based on the hydrocarbon content, and using the obtained fuel vapor content as the background value.

[0053] In this solution, step S1 includes steps S11, S12, and S13. Specifically, step S11 involves opening the fuel tank cap, introducing gas into the tank, and adjusting the gas input rate so that the exhaust flow rate after the vent valve of carbon canister 103 equals the reference flow rate value Q. This step is intended to simulate the flow of fuel and gas during actual refueling and ensure the accuracy of background value measurement. By precisely adjusting the gas input rate, the exhaust flow rate after the vent valve of carbon canister 103 is consistent with that during normal refueling, providing a reliable flow basis for subsequent background value measurement.

[0054] Step S12 involves collecting fuel vapor from the carbon canister via a sealed collection device 101, while maintaining the exhaust flow rate after the vent valve at a reference flow rate Q. The sealed collection device 101 plays a key role in this process, ensuring the integrity and accuracy of the gas sample. This device effectively collects fuel vapor discharged from the vent valve of the carbon canister 103 without disrupting the normal exhaust process, providing a raw sample for subsequent gas composition analysis.

[0055] Step S13 refers to measuring the hydrocarbon content in the closed collection device 101 using the gas measuring device 102, calculating the fuel vapor content based on the hydrocarbon content, and using the obtained fuel vapor content as the background value. The gas measuring device 102 usually uses high-precision detection technology, such as FID (flame ionization detector), which can accurately analyze the hydrocarbon content in the gas. Through professional calculation methods, the measured hydrocarbon content is converted into fuel vapor content to obtain a background value. This background value reflects the background level of hydrocarbons in the gas discharged from the vent valve of the carbon canister 103 under normal refueling conditions, and provides an important reference for the subsequent measurement of actual evaporative emissions during the refueling process.

[0056] The solution of this application reduces errors caused by differences in measurement conditions by simulating actual refueling conditions and precisely controlling the exhaust flow rate when measuring background values. Furthermore, by precisely adjusting the gas input rate to ensure that the exhaust flow rate after the vent valve of carbon canister 103 equals the reference flow rate value Q, the flow conditions during background value measurement are highly consistent with the actual refueling process, effectively improving the accuracy of the entire measurement process.

[0057] like Figure 4 As shown, in a specific embodiment, step S2 includes: step S21: controlling the vacuum degree and refueling rate of the collection device to be the same as the vacuum degree and refueling rate of step S1, and using the closed collection device 101 to collect fuel vapor in the fuel tank 110 and the carbon canister 103; step S22: using the gas measuring device 102 to measure the hydrocarbon content in the closed collection device 101, calculating the fuel vapor content based on the hydrocarbon content, and using the obtained fuel vapor content as the total evaporation amount.

[0058] In this solution, step S2 includes steps S21 and S22. Specifically, in step S21, the vacuum level and refueling rate of the collection device must be strictly controlled to maintain consistency with the conditions in step S1. This ensures uniformity and comparability of measurement conditions. Simultaneously, isolation valve 111 is opened, allowing the sealed collection device 101 to simultaneously collect fuel vapor emitted from both the fuel tank 110 and the carbon canister 103. This process requires ensuring the sealing and stability of the collection device to prevent gas leakage or the intrusion of external air.

[0059] Next, step S22 is executed. In step S22, the gas in the sealed collection device 101 is analyzed using a gas measuring device 102 (e.g., an FID) to determine the hydrocarbon content. Based on the measured hydrocarbon content, a corresponding calculation method is used to determine the total evaporation rate. This total evaporation rate represents the total amount of fuel vapor emitted from the fuel tank and carbon canister 103 during refueling.

[0060] By controlling the vacuum level and refueling rate of the collection device to match those in step S1, this solution eliminates measurement errors caused by varying conditions and ensures the accuracy and comparability of measurement results. Furthermore, the sealed collection device 101 effectively collects fuel vapor emitted from the fuel tank 110 and carbon canister 103, preventing the impact of gas leakage or external air on measurement results.

[0061] In a specific embodiment, the collection time of step S1 and step S2 is equal, and both are equal to the time required to fill the fuel tank.

[0062] In this solution, the collection duration for both steps S1 and S2 is the same as the time required to fill the tank. This ensures a uniform collection time and covers the entire refueling process, from the beginning to the tank being full, ensuring that the measured data closely corresponds to the actual refueling process. This not only improves measurement accuracy by avoiding incomplete samples or errors caused by improper collection timing, ensuring that the gas samples fully reflect emissions at all stages; it also ensures consistent measurement conditions, facilitates comparison and analysis of measurement results, and enhances measurement reliability and comparability.

[0063] The measurement method of the present application uses a closed collection device 101 to simultaneously collect fuel vapor in the fuel tank 110 and the carbon canister 103, comprehensively obtaining the evaporative emissions during the refueling process, avoiding inaccurate data caused by collecting oil and gas at only a single location, and making the measurement results more realistic and reliable. At the same time, in steps S1 and S2, the vacuum degree, refueling rate, and collection time of the collection device are strictly controlled to be consistent with the time it takes to fill the tank, eliminating measurement errors caused by changes in conditions and ensuring the accuracy and comparability of the results. In addition, by measuring the background value in the non-refueling state and the total evaporation value in the refueling state, and calculating the difference between the two, the interference of background factors is effectively eliminated, so that the measurement results more accurately reflect the actual fuel vapor emissions generated during the refueling process.

[0064] Although multiple embodiments of the present application have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art can conceive of many changes, modifications, and alternatives without departing from the thought and spirit of the present application. It should be understood that in the process of practicing the present application, various alternatives to the embodiments of the present application described herein can be adopted. The accompanying claims are intended to define the scope of protection of the present application and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A device for measuring the emission of fuel vapor during vehicle refueling, characterized in that: include: A closed collection device connected to the carbon canister vent valve via a first connecting line and connected to the fuel tank port via a second connecting line; as well as A gas measuring device is connected to the closed collecting device and is used to detect the content of fuel vapor collected by the closed collecting device.

2. The device according to claim 1, characterized in that A vacuum pump is integrated inside the closed collection device, and the vacuum degree of the vacuum pump is lower than the oil and gas recovery vacuum degree of the refueling gun.

3. The device according to claim 2, characterized in that The closed collection device is internally integrated with a pressure sensor and a temperature sensor.

4. The device according to any one of claims 1 to 3, characterized in that The closed collection device further includes an isolation valve, which is provided on the connecting pipe between the carbon canister and the fuel tank; the closed collection device is configured to have two working modes: First mode: When the isolation valve is disconnected, only the fuel vapor in the carbon canister is collected; Second mode: When the isolation valve is turned on, fuel vapor is collected in the fuel tank and carbon canister at the same time.

5. The device according to claim 1, characterized in that The gas measurement device is a flame ionization detector (FID), which can measure the total mass of hydrocarbons in the closed collection device.

6. A method for measuring the emission of fuel vapor during vehicle refueling using the measuring device according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step S1: In a non-refueling state, collecting fuel vapor in the carbon canister as a background value; Step S2: In the refueling state, the fuel vapor content in the fuel tank and the carbon canister is collected as the total evaporation amount; Step S3: Calculate the difference between the total evaporation amount and the background value, and use the difference as the emission amount of fuel vapor during the refueling process.

7. The method according to claim 6, characterized in that Before executing step S1, step S0 needs to be executed: simulating normal refueling conditions, measuring the exhaust flow rate after the carbon canister vent valve, and recording the reference flow value Q after the flow rate stabilizes.

8. The method according to claim 7, characterized in that The step S1 comprises: Step S11: opening the fuel tank cap, introducing gas into the fuel tank, and adjusting the gas input rate so that the exhaust flow rate after the carbon canister vent valve is equal to the reference flow value Q; Step S12: collecting fuel vapor in the carbon canister through the closed collection device; Step S13: using a gas measuring device to measure the hydrocarbon content in the sealed collection device, calculating the fuel vapor content based on the hydrocarbon content, and using the obtained fuel vapor content as a background value.

9. The method according to any one of claims 6 to 8, characterized in that: The step S2 comprises: Step S21: Controlling the vacuum degree and refueling rate of the collection device to be the same as the vacuum degree and refueling rate of step S1, and using the sealed collection device to collect fuel vapor in the fuel tank and carbon canister; Step S22: Measure the hydrocarbon content in the sealed collection device using a gas measuring device, calculate the fuel vapor content based on the hydrocarbon content, and use the obtained fuel vapor content as the total evaporation amount.

10. The method according to claim 6, characterized in that The collection time of step S1 and step S2 is equal, and both are equal to the time required to fill the fuel tank.

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