A method for determining the adsorption capacity of a carbon canister

Abstract

This invention discloses a method for determining the adsorption capacity of a charcoal canister, relating to the field of automotive fuel evaporative emission control and component performance testing technology. It includes the following steps: Step 1: Obtain the current internal vapor pressure P of the fuel tank using a fuel tank pressure sensor. 1， Step 2: Determine if the internal pressure P1 of the fuel tank is less than or equal to 1 kPa. This threshold can be set to any value not exceeding 3.5 kPa, depending on the actual vehicle model. This invention utilizes the existing vehicle structure and data accumulated from numerous experiments and research projects to form a theoretical model for effectively estimating the working capacity of the charcoal canister and the amount of fuel tank vapor emissions. By comparing these two sets of data, it determines whether the charcoal canister has the ability to adsorb and discharge fuel vapors. The product requires no additional hardware; it only needs to analyze existing vehicle data to achieve its function. It is low-cost, highly efficient, and has good regulatory compliance.

Description

Technical Field

[0001] This invention relates to the field of automotive fuel evaporation emission control and component performance testing technology, specifically a method for determining the adsorption capacity of a carbon canister. Background Technology

[0002] In the fuel system of light-duty gasoline vehicles, the gasoline stored in the fuel tank will generate a large amount of gasoline vapor during use due to temperature changes, vehicle shaking, and other reasons. For models that use a sealed fuel tank, this vapor will accumulate inside the fuel tank, causing the internal pressure of the fuel tank to increase.

[0003] During actual vehicle use, the fuel tank isolation valve (also known as the fuel tank shut-off valve or FTIV) needs to be opened in the following situations to release the vapor in the fuel tank into the charcoal canister for adsorption:

[0004] When refueling, you need to open the fuel tank cap to add gasoline. Before that, you need to vent the vapor in the fuel tank into the charcoal canister.

[0005] When diagnosing a fuel tank leak, it is necessary to perform a sealing test on the fuel tank system and first vent the steam.

[0006] When the fuel tank is under safety protection, if the pressure in the fuel tank exceeds the safety threshold, steam needs to be released to reduce the pressure.

[0007] The charcoal canister is a core component of the vehicle's evaporative emission control system. It is filled with activated carbon material, which can adsorb gasoline vapor. However, the adsorption capacity of the charcoal canister is limited. When the amount of vapor adsorbed by the charcoal canister reaches saturation, it can no longer adsorb more vapor.

[0008] The core problem this invention aims to solve is: how to determine whether the charcoal canister still has sufficient adsorption capacity to safely adsorb all the fuel vapor that is about to be discharged from the fuel tank before opening the fuel tank isolation valve. If the fuel tank isolation valve is opened when the charcoal canister does not have sufficient adsorption capacity, HC (hydrocarbon) pollutants will be directly emitted into the atmosphere, causing environmental pollution and potentially leading to vehicles failing to meet environmental regulations and facing legal risks. Therefore, this invention proposes a novel method for determining the adsorption capacity of the charcoal canister. Summary of the Invention

[0009] The purpose of this invention is to provide a method for determining the adsorption capacity of a carbon canister, in order to solve the problems mentioned in the background art.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a method for determining the adsorption capacity of a carbon canister, comprising the following steps:

[0011] Step 1: Obtain the current internal steam pressure P1 of the oil tank using the oil tank pressure sensor.

[0012] Step 2: Determine if the internal pressure P1 of the fuel tank is less than or equal to 1 kPa. This threshold can be set to any value not exceeding 3.5 kPa, depending on the actual vehicle model.

[0013] If P1≤1kPa, it means that the steam pressure inside the oil tank is extremely low, and there is almost no steam that needs to be discharged. The oil tank isolation valve can be opened safely, and the process is considered complete.

[0014] If P1 > 1 kPa, it indicates that there is steam at a certain pressure in the oil tank, and further calculation and judgment are required before proceeding to step 3.

[0015] Step 3: Record the following parameters: the time T when the fuel tank shut-off valve last opened. s The current fuel volume inside the fuel tank is V1.

[0016] Step 4: Based on the internal pressure P1 of the fuel tank and the nominal volume V of the fuel tank n Given the current fuel volume V1, calculate the mass m1 of steam discharged from the fuel tank using a closed fuel tank steam emission calculation model.

[0017] Step 5: Calculate the current working capacity m2 of the charcoal canister.

[0018] Step 6: Compare the steam emission m1 from the oil tank with the current working capacity m2 of the charcoal canister, and determine whether to open the oil tank isolation valve.

[0019] Further, the calculation of the current working capacity m2 of the charcoal canister also includes the following steps:

[0020] 5a; Calculate the cumulative desorption amount V, calculated from the last FTIV start time T. s up to the current time T f During the time interval, the cumulative opening time S1 of the desorption solenoid valve is used to calculate the cumulative desorption volume V using the desorption amount calculation model;

[0021] 5b: Calculate the current working capacity (m2) of the carbon canister, and combine the desorption capacity (V) and the declared volume (V) of the carbon canister. c Substitute the initial working capacity M of the charcoal canister into the charcoal canister working capacity calculation model to calculate the current remaining working capacity m2 of the charcoal canister.

[0022] To further elaborate on this scheme, step 6, determining whether to open the fuel tank isolation valve, includes the following steps:

[0023] If m1≤PF×m 2， The charcoal canister has sufficient adsorption capacity and can open the fuel tank isolation valve normally;

[0024] If m1 > PF × m2, the adsorption capacity of the charcoal canister is insufficient to safely adsorb all the steam about to be discharged, and the oil tank isolation valve must not be opened. In this case, the desorption operation needs to continue, and the assessment should be repeated after the charcoal canister's capacity is restored.

[0025] Further, the method for calculating the mass m1 of steam discharged from the oil tank is as follows:

[0026] .

[0027] Further, regarding this scheme, the calculation method for the current working capacity m2 of the carbon canister is as follows:

[0028] .

[0029] Furthermore, the low-pressure threshold of the fuel tank is set to no more than 1 kPa.

[0030] Further, the method for judging the adsorption capacity of the charcoal canister also includes a continuous cumulative tracking step of the remaining working capacity of the charcoal canister: after each judgment in step S6, the current working capacity m2 of the charcoal canister is recorded. In subsequent scenarios where the oil tank isolation valve needs to be opened multiple times, incremental calculations are performed based on the previous judgment result to track the changing trend of the remaining working capacity of the charcoal canister, so as to determine whether the adsorption capacity of the charcoal canister is still sufficient during continuous operation.

[0031] Further, the calculation method for the desorption amount calculation model is as follows:

[0032] .

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] This method for determining the adsorption capacity of the charcoal canister utilizes the existing vehicle structure and data accumulated from numerous experiments and research projects to form a theoretical model that effectively estimates the working capacity of the charcoal canister and the amount of fuel vapor emitted from the fuel tank. By comparing the two sets of data, it can be determined whether the charcoal canister has the ability to adsorb and discharge fuel vapor. The product requires no additional hardware; it only needs to analyze the existing vehicle data to achieve the function. It is low-cost, highly efficient, and has good regulatory compliance. Attached Figure Description

[0035] Figure 1 This is a schematic flowchart of the carbon canister adsorption capacity determination method of the present invention. Detailed Implementation

[0036] 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.

[0037] This invention uses operational data obtained from existing vehicle sensors, combined with a theoretical calculation model verified through extensive testing, to estimate two key data points: 1. The amount of vapor m1 that will be discharged from the fuel tank; 2. The remaining adsorption capacity m2 of the charcoal canister. By comparing these two data points, it can be determined whether the fuel tank isolation valve can be safely opened.

[0038] This invention is mainly applicable to light-duty fuel vehicles that use a sealed fuel tank and whose tank pressure is below 40 kPa.

[0039] Figure 1 A schematic diagram of a typical fuel system and desorption system involved in this invention is shown. The system mainly includes the following components:

[0040] Fuel tank: A sealed container for storing gasoline. The fuel tank is equipped with a pressure sensor to monitor the internal pressure P1 in real time.

[0041] Fuel tank shut-off valve (FTIV): Installed on the pipeline between the fuel tank and the charcoal canister, it controls whether fuel tank vapor can be discharged into the charcoal canister.

[0042] Charcoal canister: A container filled with activated carbon, which uses the adsorption properties of activated carbon to capture and store gasoline vapors. The charcoal canister has a rated volume V. c And initial working ability M.

[0043] Desorption solenoid valve: Installed on the pipeline between the charcoal canister and the engine intake manifold, it controls whether the desorption operation is performed. When the valve is open, the negative pressure generated by the intake manifold draws air through the charcoal canister, carrying away the vapor adsorbed in the charcoal canister and sending it into the engine for combustion.

[0044] Desorption pipe: A pipe that connects the charcoal canister to the engine intake manifold.

[0045] Vent pipe: The pipe connecting the fuel tank and the charcoal canister.

[0046] like Figure 1 As shown, the present invention provides a technical solution: a method for determining the adsorption capacity of a carbon canister, comprising the following steps:

[0047] Step 1: Obtain the current internal steam pressure P1 of the oil tank using the oil tank pressure sensor.

[0048] Step 2: Determine if the internal pressure P1 of the fuel tank is less than or equal to 1 kPa. This threshold can be set to any value not exceeding 3.5 kPa, depending on the actual vehicle model.

[0049] If P1≤1kPa, it means that the steam pressure inside the oil tank is extremely low, and there is almost no steam that needs to be discharged. The oil tank isolation valve can be opened safely, and the process is considered complete.

[0050] If P1 > 1 kPa, it indicates that there is steam at a certain pressure in the oil tank, and further calculation and judgment are required before proceeding to step 3.

[0051] Step 3: Record the following parameters: the time T when the fuel tank shut-off valve last opened. s The current fuel volume inside the fuel tank is V1.

[0052] Step 4: Based on the internal pressure P1 of the fuel tank and the nominal volume V of the fuel tank n Given the current fuel volume V1, use the closed fuel tank steam emission calculation model to calculate the mass m1 (unit: grams) of steam discharged from the fuel tank.

[0053] Step 5: Calculate the current working capacity m2 of the charcoal canister;

[0054] Step 5a: Calculate the cumulative desorption amount V, which is calculated from the last time FTIV was started, T. s up to the current time T f The cumulative opening time S1 (in seconds) of the desorption solenoid valve during the time interval is calculated using the desorption volume calculation model, and the cumulative desorption volume V (in liters) is calculated.

[0055] Step 5b: Calculate the current working capacity m2 of the carbon canister, and combine the desorption capacity V and the declared volume V of the carbon canister. c Substitute the initial working capacity M of the charcoal canister into the charcoal canister working capacity calculation model to calculate the current remaining working capacity m2 (unit: grams) of the charcoal canister.

[0056] Step 6: Compare the steam emission rate m1 from the oil tank with the current working capacity m2 of the charcoal canister, where PF is the preset safety factor.

[0057] If m1≤PF×m2: The charcoal canister has sufficient adsorption capacity and the oil tank isolation valve can be opened normally;

[0058] If m1 > PF × m2: The adsorption capacity of the charcoal canister is insufficient to safely adsorb all the steam about to be discharged, and the oil tank isolation valve must not be opened. In this case, the desorption operation needs to continue, and the judgment should be re-evaluated after the charcoal canister capacity is restored.

[0059] To ensure the smooth implementation of the above embodiments, it is necessary to understand the calculation model for the steam emission of a closed oil tank, i.e., the calculation method for m1, as follows:

[0060]

[0061] The gasoline vapor inside a sealed fuel tank can be considered as a gas, and the relationship between its pressure, volume, temperature, and mass follows the ideal gas law in physics:

[0062]

[0063] Where: P is the absolute pressure of the gas (unit: Pa); V is the volume occupied by the gas (unit: m³); n is the amount of substance of the gas (unit: mol); R is the gas constant, taken as 8.314 J / (mol·K); T is the thermodynamic temperature of the gas (unit: K, i.e., Celsius +273.15).

[0064] Furthermore, the amount of substance n of a gas and the mass m of a gas are converted through the molar mass M: m = n × M. The main components of gasoline vapor are hydrocarbons such as butane and pentane, and their average molar mass M is about 70 g / mol. Combining the above relationships, we can obtain the calculation formula for m1.

[0065] In practical applications, the parameters of the basic formula need to be adjusted to adapt to the specific scenarios of fuel tank venting, including:

[0066] Calculation of vapor phase volume: The vapor phase space of a fuel tank is not simply equal to the tank volume minus the fuel volume. There is also space for gasoline vapor diffusion above the gasoline surface. The actual vapor phase space needs to consider the expansion effect. According to experimental data, the actual vapor phase space is approximately 1.3 times the nominal vapor phase space, i.e., Vva gas =1.3×(V n -V1).

[0067] Determination of effective exhaust pressure difference: After opening the oil tank isolation valve, the steam in the oil tank will not be completely vented. After the steam is vented, a certain pressure will remain in the oil tank. According to a large number of test experiences, the residual pressure is about 2.5 kPa (this value is usually between 0 and 5 kPa). Therefore, the effective exhaust pressure difference is ΔP = P1 - 2.5.

[0068] Temperature determination: To simplify calculations, room temperature of 25°C is taken as the reference temperature.

[0069] The introduction of correction factor: There is a deviation between theoretical calculation and actual situation. This is due to the combined effects of factors such as different vapor compositions of different oil products, temperature changes, and dynamic balance between vapor and liquid gasoline. Therefore, it is necessary to introduce a correction factor k', whose value is between 0.25 and 0.78. We take k' = 0.5.

[0070] Taking into account the above parameters and adjustments, the final calculation formula is:

[0071]

[0072] Where: m1 is the mass of gasoline vapor discharged from the fuel tank (g); P1 is the current internal pressure of the fuel tank (kPa); 2.5 is the residual pressure of the fuel tank after discharge (kPa); 1.3 is the gas phase space expansion coefficient; V n V1 is the nominal volume of the fuel tank (L); V2 is the current fuel volume (L); 0.01412 is the comprehensive constant coefficient.

[0073] Regarding the above embodiments, it is also necessary to determine the desorption amount calculation model. The physical essence of the desorption process is that when the engine is running, the intake manifold generates negative pressure. When the desorption solenoid valve opens, the external air flows into the intake manifold through the charcoal canister under the drive of the pressure difference. When the air flows through the charcoal canister, it carries away the gasoline vapor adsorbed in the charcoal canister and sends it into the engine for combustion. To calculate the desorption amount, it is first necessary to determine the air flow rate in the desorption pipe.

[0074] The flow of air in a pipe follows the Darcy-Weisbach Equation, which describes the pressure loss caused by frictional resistance when a fluid flows in a pipe:

[0075]

[0076] Where: ΔP is the pressure difference between the two ends of the pipe (Pa); f is the pipe friction coefficient, taken as 0.0218; L is the total length of the pipe (m); d is the inner diameter of the pipe (m); ρ is the air density, taken as 1.2 kg / m³; v is the air velocity (m / s).

[0077] Meanwhile, according to the continuity equation, the volumetric flow rate Q of the fluid in the pipe is equal to the flow velocity v multiplied by the pipe cross-sectional area A:

[0078]

[0079] Solving the Darcy-Weisbach formula and the continuity equation simultaneously yields an expression for the volumetric flow rate Q. For ease of engineering application, the units are converted to commonly used engineering units (pipe diameter mm, pressure drop kPa, pipe length m, flow rate L / min), simplifying it as follows:

[0080]

[0081] There is a discrepancy between the theoretical formula and the actual situation, so a correction coefficient k needs to be introduced to obtain a new formula:

[0082]

[0083] The method for determining k involves setting up a test bench in the laboratory, using a flow meter to measure the actual flow rate of the desorption pipeline under different operating conditions, and simultaneously calculating the theoretical flow rate under the same operating conditions using a theoretical formula. The ratio of the two is taken as the k value. Through extensive testing with different vehicle models and different pipeline configurations, the k value is distributed between 0.25 and 0.4. A k value of 0.3094, covering 90% of usage scenarios, is selected. The corrected formula is as follows:

[0084]

[0085] For vehicles with sealed fuel tanks, considering normal driving and medium load conditions, the desorption pipe negative pressure ΔP can be taken as an empirical value of 45 kPa. In addition, the solenoid valve opening coefficient (taken as 0.2) and the solenoid valve response delay coefficient (taken as 0.7) also need to be considered. Taking all these factors into account, the desorption flow rate Q is finally simplified to:

[0086]

[0087] The desorption volume V equals the desorption flow rate Q multiplied by the cumulative opening time S1 of the desorption solenoid valve.

[0088]

[0089] When the pressure difference ΔP in the desorption pipeline changes with time, the integral method should be used for calculation:

[0090]

[0091] It involves summing up the traffic at every instant.

[0092] To ensure the smooth implementation of the above embodiments, it is also necessary to understand the calculation model of the working capacity of the charcoal canister, that is, to calculate m2. The initial working capacity M of the charcoal canister refers to the maximum mass of gasoline vapor that the charcoal canister can adsorb in a brand new state. The current working capacity m2 refers to the actual adsorption capacity that the charcoal canister still has after a period of use and desorption. The core objective of this model is to estimate how much adsorption capacity the charcoal canister has recovered based on the cumulative desorption amount V.

[0093] The adsorption and desorption of carbon canisters are complex physicochemical processes, making it difficult to establish an accurate model through pure theoretical derivation. Therefore, this invention employs an empirical formula method based on extensive experimental data. Numerous desorption-adsorption cycle experiments were conducted in the laboratory for carbon canisters of different specifications, recording V (desorption amount) and Vdesorption in each experimental group. c Measured data of (charcoal canister volume), M (initial capacity), and m2 (current capacity) were used for correlation analysis and curve fitting. The results showed that m2 is directly proportional to M, while the desorption recovery ratio is related to V / V. c The natural logarithm of the equation shows a linear relationship, and based on this, the following fit is obtained:

[0094]

[0095] The part in parentheses in the formula represents the recovery ratio of the adsorption capacity of the activated carbon canister (value from 0 to 1): when the desorption amount V=0, the ratio is the smallest and the activated carbon canister is almost saturated. As the desorption amount V increases, the ratio increases and the capacity is recovered more. The characteristic of the natural logarithm Ln function, which grows rapidly in the early stage and slowly in the later stage, is exactly consistent with the physical characteristics of activated carbon canister desorption. In the early stage of desorption, a large amount of steam is quickly carried away. In the later stage, the residual steam has a stronger binding force with activated carbon, and a larger desorption amount is required for further recovery.

[0096] Using the three calculation models above, we obtained the oil tank steam emission m1, the cumulative desorption amount V, and the current working capacity of the charcoal canister m2, respectively. The final judgment logic is as follows:

[0097] If m1 ≤ PF × m2, then the fuel tank isolation valve may be opened.

[0098] If m1 > PF × m2, then the fuel tank isolation valve is not allowed to be opened.

[0099] PF is the safety factor, which is used to reserve a safety margin based on the calculation results to ensure the reliability of the judgment. When the internal pressure of the oil tank P1≤1kPa, it is directly determined that the oil tank isolation valve can be opened without calculation. This embodiment can also continuously accumulate and track the remaining working capacity of the charcoal canister, and track the changing trend of the remaining working capacity of the charcoal canister in scenarios where the oil tank isolation valve needs to be opened multiple times.

[0100] To reduce the resource consumption of real-time computing, this embodiment can also implement a fast estimation method. This method adopts more conservative operating condition assumptions, introduces a larger safety factor, and takes the conservative value of the parameters in each calculation model under the most unfavorable operating conditions, so that the calculation results are more safe or tend to not allow the valve to be opened easily. This sacrifices a small amount of judgment accuracy in exchange for faster calculation speed.

[0101] The following example illustrates the complete execution process of the judgment method of this invention, assuming the following parameters:

[0102] Vehicle parameters: Nominal fuel tank capacity V n =50L; Charcoal canister volume V c =1.0L; Initial working capacity of the carbon canister M=50g; Inner diameter of the desorption tube d=8mm; Total length of the desorption tube L=2m; Safety factor PF=0.8.

[0103] Current status: fuel tank pressure P1=15kPa; fuel volume in fuel tank V1=35L; cumulative opening time of desorption solenoid valve S1=600s.

[0104] Execution process:

[0105] Step 1: Read P1 = 15 kPa;

[0106] Step 2: Determine that P1 = 15 kPa > 1 kPa, and enter the calculation process;

[0107] Step 3: Record the parameters P1 = 15 kPa, V1 = 35 L;

[0108] Step 4: Calculate the steam emission amount m1 ≈ 0.974 g;

[0109] Step 5a: Calculate the cumulative desorption amount V ≈ 113.6 L;

[0110] Step 5b: Calculate the current working capacity of the carbon canister m2 ≈ 40.93 g;

[0111] Step 6: Finally, judge that PF × m2 = 0.8 × 40.93 = 32.74 g. Since m1 = 0.974 g < PF × m2 = 32.74 g, the judgment result is that the carbon canister has sufficient adsorption capacity and the fuel tank isolation valve can be safely opened.

[0112] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended embodiments and their equivalents.

Claims

1. A method for determining the adsorption capacity of a carbon canister, characterized in that, Includes the following steps: Step 1: Obtain the current internal steam pressure P1 of the oil tank using the oil tank pressure sensor. Step 2: Determine if the internal pressure P1 of the fuel tank is less than or equal to 1 kPa. If P1≤1kPa, the oil tank isolation valve is opened safely, and the judgment process ends. If P1 > 1 kPa, further calculation and judgment are performed, and then proceed to step 3. Step 3: Record the following parameters: the time T when the fuel tank shut-off valve last opened. s And the current fuel volume V1 inside the fuel tank. Step 4: Based on the internal pressure P1 of the fuel tank and the nominal volume V of the fuel tank n Given the current fuel volume V1, the mass m1 of steam discharged from the fuel tank is calculated using a closed fuel tank steam emission calculation model. Step 5: Calculate the current working capacity m2 of the charcoal canister. Step 6: Compare the steam emission m1 from the oil tank with the current working capacity m2 of the charcoal canister, and determine whether to open the oil tank isolation valve.

2. The method for determining the adsorption capacity of a carbon canister according to claim 1, characterized in that: Calculating the current working capacity m2 of the charcoal canister also includes the following steps: 5a: Calculate the cumulative desorption amount V, which is calculated from the last time FTIV was started, T. s up to the current time T f During the time interval, the cumulative opening time S1 of the desorption solenoid valve is used to calculate the cumulative desorption volume V using the desorption amount calculation model; 5b: Calculate the current working capacity (m2) of the carbon canister, and combine the desorption capacity (V) and the declared volume (V) of the carbon canister. c Substitute the initial working capacity M of the charcoal canister into the charcoal canister working capacity calculation model to calculate the current remaining working capacity m2 of the charcoal canister.

3. The method for determining the adsorption capacity of a carbon canister according to claim 1, characterized in that: Whether to open the fuel tank isolation valve in step 6 includes the following determination steps: If m1≤PF×m2, the charcoal canister has sufficient adsorption capacity and the oil tank isolation valve can be opened normally. If m1 > PF × m2, the adsorption capacity of the charcoal canister is insufficient to safely adsorb all the steam that is about to be discharged. The oil tank isolation valve must not be opened. In this case, the desorption operation needs to continue, and the judgment should be made again after the charcoal canister capacity is restored.

4. The method for determining the adsorption capacity of a carbon canister according to claim 1, characterized in that: The method for calculating the mass m1 of steam discharged from the oil tank is as follows: 。 5. The method for determining the adsorption capacity of a carbon canister according to claim 1, characterized in that: The calculation method for the current working capacity m2 of the carbon canister is as follows: 。 6. The method for determining the adsorption capacity of a carbon canister according to claim 1, characterized in that: The low-pressure threshold of the fuel tank is set to no more than 1 kPa.

7. The method for determining the adsorption capacity of a carbon canister according to claim 1, characterized in that: The method for judging the adsorption capacity of the charcoal canister also includes a continuous cumulative tracking step of the remaining working capacity of the charcoal canister: after each judgment in step S6, the current working capacity m2 of the charcoal canister is recorded. In subsequent scenarios where the oil tank isolation valve needs to be opened multiple times, incremental calculations are performed based on the previous judgment result to track the changing trend of the remaining working capacity of the charcoal canister, so as to determine whether the adsorption capacity of the charcoal canister is still sufficient during continuous operation.

8. A method for determining the adsorption capacity of a carbon canister according to claim 2, characterized in that: The calculation method for the desorption amount calculation model is as follows: 。

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