Method and device for testing degradation rate of working capacity of oil gas recovery system of vehicle

Abstract

The invention discloses a method and device for testing the working capacity degradation rate of a vehicle oil gas recovery system, and the method comprises the steps: dividing the working capacity of the oil gas recovery system into anti-infiltration capacity and carbon canister working capacity according to a proportionality coefficient, and dividing the carbon canister working capacity into refueling working capacity and day and night breathing working capacity according to a proportionality coefficient; the oil gas recovery system anti-infiltration capacity and the carbon canister working capacity are truly quantified through a bench test method, and the oil gas recovery system working capacity degradation rate is calculated based on test results of the new vehicle anti-infiltration capacity, the old vehicle anti-infiltration capacity and the carbon canister working capacity and the proportionality coefficient; according to the invention, the problem of low accuracy of calculating the working capability degradation rate of the oil gas recovery system by an empirical method is effectively solved, and a timeliness detection report or a technical rectification scheme of the vehicle oil gas recovery system can be obtained by using the test method.

Description

Technical Field

[0001] The invention belongs to the field of automobile emission control, and in particular relates to a method and a device for testing the degradation rate of working capacity of a vehicle oil and gas recovery system. Background Art

[0002] Gasoline is a volatile fuel. Changes in ambient temperature, driving shaking, and the refueling process will cause the fuel tank to emit a large amount of hydrocarbons. According to emission source analysis reports from multiple regions, volatile organic compounds in vehicle evaporative emissions are an important source of pollution in urban air environments. Gasoline vehicles are equipped with an oil and gas recovery system to control evaporative emissions. However, as the age / mileage of the vehicle increases, the working capacity of the oil and gas recovery system will show a gradual downward trend. This phenomenon is called deterioration or aging. Deterioration is caused by two reasons. On the one hand, the aging of the seal reduces the anti-permeability working capacity of the fuel system. On the other hand, some substances in the activated carbon are difficult to desorb, resulting in a decrease in the working capacity of the carbon canister. The deterioration of the working capacity of the oil and gas recovery system will seriously affect the timeliness of evaporative emission control.

[0003] Since the regulations do not require that the vehicle oil and gas recovery system be put on line for inspection after reaching a certain age, currently both the inspection agencies and the vehicle manufacturers pay little attention to the degradation of the working ability of the vehicle oil and gas recovery system. With the continuous tightening of emission regulations, more and more attention will be paid to the timeliness of the oil and gas recovery system in the future. The EU has proposed a carbon canister degradation test method, which is to load the carbon canister 300 times in a short period of time to simulate aging; some suppliers have also carried out fuel system permeability aging tests, and then tested the system permeability after 20 weeks and 40 weeks of high-temperature aging. Based on these component tests, an estimation model for the degradation rate of the working ability of the oil and gas recovery system can be derived. However, this fitting calculation cannot comprehensively consider the weight of the anti-permeability ability and the working ability of the carbon canister, and on the other hand, it cannot accurately calculate the degradation rate of the vehicle oil and gas recovery system. At present, there is a lack of an accurate test method for the degradation rate of the working ability of the oil and gas recovery system. Proposing a test method for the degradation rate of the working ability of the vehicle oil and gas recovery system is of great significance to reducing vehicle carbon emissions. Summary of the invention

[0004] Purpose of the invention: In view of the deficiencies in the prior art, the present invention provides a method and device for testing the degradation rate of the working capacity of a vehicle oil and gas recovery system, which effectively solves the problem of low accuracy in calculating the degradation rate of the working capacity of the oil and gas recovery system by the empirical method. This testing method can be used to obtain a timeliness inspection report or a technical rectification plan for the vehicle oil and gas recovery system.

[0005] Technical solution: A method for testing the degradation rate of the working capacity of a vehicle oil and gas recovery system, comprising the following steps:

[0006] S1. The working capacity of the oil and gas recovery system is divided into the anti-permeability capacity and the carbon canister working capacity, and a proportional coefficient is assigned;

[0007] S2. The bench test begins, and the anti-penetration capability test of the oil and gas recovery system of the new vehicle is carried out;

[0008] S3. Test the working capacity of the carbon canister of the oil and gas recovery system of the new car, including the refueling working capacity of the carbon canister and the day and night breathing working capacity of the carbon canister, and determine the proportional coefficient of the two based on the test results;

[0009] S4. Test the anti-penetration capability of the oil and gas recovery system of the old car and the working capability of the carbon canister;

[0010] S5. Calculate the degradation rate of the oil and gas recovery system's working capacity based on the bench test data of new and old vehicles and the proportional coefficient.

[0011] The proportionality coefficient in S1 is calculated based on the contribution of permeation emissions and carbon canister escape emissions to the annual evaporative emissions of the vehicle. The anti-permeability coefficient K p , Carbon canister working capacity coefficient K f Specifically:

[0012]

[0013] Where: M p (g / day) is the average daily permeation emission of the fuel system, α is the average annual breakdown number of the carbon canister, M f (g) is the average emission from each carbon canister breakdown, β is the average annual number of refueling times for the vehicle, M r (g) The average emission from the charcoal canister during each refueling.

[0014] The S2 is specifically:

[0015] S21. The test vehicle pushes the evaporation tank of the whole vehicle, the fuel tank is drained, and the refueling equipment is filled with 40% of the nominal volume of the fuel tank;

[0016] S22, connecting the atmospheric port of the carbon canister to a long air pipe, and connecting the other end of the long air pipe to an auxiliary carbon canister placed outside the bin;

[0017] S23, the evaporation chamber is turned on for a day and night temperature cycle, and the concentration of hydrocarbons in the evaporation chamber before and after the test is monitored by a hydrogen flame ionization detector. The calculation results are converted into vehicle background and permeation emissions, recorded as M total (g);

[0018] S24, use a vacuum pump to drain the fuel in the fuel tank, let it stand for a while, repeat S22 and S23, and convert the calculation result into the background emission of the non-fuel system of the whole vehicle, recorded as M background (g);

[0019] The conversion calculation method is as follows:

[0020]

[0021] Where: M(g) is the emission; V is the net volume of the closed room corrected by the volume of the car (windows and trunk open). If the volume of the car is not determined, subtract 1.42m 3 ; k is 1.2*(12+H / C); C HC (ppm) is the hydrocarbon concentration in the closed room; P (kPa) is the atmospheric pressure; T 24 (K) is the ambient temperature of the sealed room after one day and night; i represents the initial reading; M HC，出 (g) is the mass of hydrocarbons discharged from a closed chamber of constant volume when a hot soak or day and night ventilation test is carried out in the closed chamber of constant volume; M HC，入 (g) The mass of hydrocarbons entering a closed chamber of constant volume when the chamber is used for heat soak or day and night ventilation test;

[0022] M total (g) and M background (g) The corresponding results can be obtained through the above conversion calculation method;

[0023] S25, M total With M background The difference is the anti-permeability capacity W of the new car oil and gas recovery system p1 (g / test);

[0024] In S3, the working capacity of the carbon canister is divided into the refueling working capacity W r (g / L) and diurnal respiratory work capacity W b (g / L), and determine the proportionality coefficient based on the bench test results. The specific test method is as follows:

[0025] S31. Charcoal canister refueling capacity test: disconnect the charcoal canister from the fuel tank, connect the charcoal canister adsorption port to the loading port of the oil and gas loading device, connect one end of the long gas pipe to the charcoal canister atmospheric port, and the other end to the micro evaporation chamber. Before the test, the oil and gas loading device desorbs 600BV of the charcoal canister, and then the oil and gas loading device loads the charcoal canister at a rate of 2700g / h. When the mass increment of hydrocarbons in the micro evaporation chamber exceeds 50mg, stop loading. The ratio of the total loading amount to the charcoal canister volume is the initial charcoal canister refueling capacity W r1 ;

[0026] S32, carbon canister day and night breathing capacity test: During the test, the oil and gas loading equipment loads the carbon canister at a rate of 2.5g / h. The other steps are the same as S31. The ratio of the total loading amount to the carbon canister volume is the initial carbon canister day and night breathing capacity W b1 ;

[0027] S33, carbon canister refueling capacity ratio coefficient K r The ratio coefficient K of the day and night breathing capacity of the charcoal canister b They are:

[0028]

[0029] Where: W b1 W is the initial charcoal canister's day and night breathing capacity; r1 Refueling capacity for initial canister.

[0030] In S4, the test method for the old car is the same as that for the new car, and the test result of the anti-penetration ability of the old car is recorded as W p2 , the charcoal canister refueling capacity test result is recorded as W r2 , the test result of the day and night breathing capacity of the degraded carbon canister is recorded as W b2 ;

[0031] The oil and gas recovery system working capacity degradation rate in S5 The calculation method is:

[0032]

[0033] Where: W p1 W is the initial canister anti-permeability capability; p2 To degrade the anti-permeability capability of the carbon canister; b2 To degrade the day and night breathing capacity of the carbon canister; r2 Deterioration of the refueling capacity of the carbon canister; K p K is the anti-penetration coefficient; f K is the working capacity coefficient of the carbon canister; r Refueling capacity ratio coefficient for charcoal canister; K b It is the ratio coefficient of the day and night breathing capacity of the carbon canister.

[0034] A device for implementing the vehicle oil and gas recovery system working capacity degradation rate test method, characterized by comprising: a vehicle evaporation chamber, a micro evaporation chamber, a hydrogen flame ionization detector, a refueling device, a vacuum pump, a long gas pipe, an oil and gas loading device, and an auxiliary carbon canister;

[0035] The whole vehicle evaporation chamber and the micro evaporation chamber are equipped with a hydrogen flame ionization detector;

[0036] The refueling equipment, vacuum pump, oil and gas loading equipment, and auxiliary carbon canister are all installed outside the evaporation chamber;

[0037] The refueling device is connected to the fuel tank of the test vehicle in the evaporation chamber of the whole vehicle when the vehicle is refueled;

[0038] The vacuum pump is connected to the fuel tank of the test vehicle in the evaporative bin of the whole vehicle to pump oil when conducting the non-fuel system evaporative emission test;

[0039] The long air pipe is connected to the atmospheric port of the carbon canister of the test vehicle and the micro evaporation chamber when testing day and night breathing emissions;

[0040] The long air pipe is connected to the atmospheric port of the vehicle carbon canister and the adsorption port of the auxiliary carbon canister when testing the permeation emission.

[0041] It can be connected to the micro evaporation chamber, auxiliary carbon canister adsorption port, and the atmospheric port of the vehicle carbon canister tested in the vehicle evaporation chamber;

[0042] The oil and gas loading device is connected to the vehicle canister desorption port of the test vehicle in the whole vehicle evaporation bin before the experiment to perform desorption before the experiment;

[0043] The oil and gas loading device is connected to the carbon canister adsorption port of the test vehicle in the evaporation bin of the whole vehicle when performing the carbon canister refueling working capacity test.

[0044] Beneficial effects: The anti-permeability capability and carbon canister working capacity of the oil and gas recovery system are truly quantified through the bench test method, and the oil and gas recovery system working capacity degradation rate is calculated based on the test results of the anti-permeability capability and carbon canister working capacity of new and old vehicles and the proportional coefficient; the problem of low accuracy of the empirical method for calculating the oil and gas recovery system working capacity degradation rate is effectively solved. This test method can be used to obtain a vehicle oil and gas recovery system timeliness inspection report or technical rectification plan. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0046] Figure 1 This is a step diagram of the method for testing the degradation rate of the working capacity of the vehicle oil and gas recovery system of the present invention.

[0047] Figure 2 This is a diagram of a testing device for the working capacity degradation rate of a vehicle oil and gas recovery system according to the present invention. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] In the description of the present invention, it is necessary to understand that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0050] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0051] like Figure 1 As shown, a method for testing the degradation rate of working capacity of a vehicle oil and gas recovery system comprises the following steps:

[0052] S1. The working capacity of the oil and gas recovery system is divided into the anti-permeability capacity and the carbon canister working capacity, and a proportional coefficient is assigned;

[0053] S2. The bench test begins, and the anti-permeability test of the oil and gas recovery system of the new vehicle is carried out;

[0054] S3. Test the working capacity of the carbon canister of the oil and gas recovery system of the new car, including the refueling working capacity of the carbon canister and the day and night breathing working capacity of the carbon canister, and determine the proportional coefficient of the two based on the test results;

[0055] S4. Test the anti-penetration capability of the oil and gas recovery system of the old car and the working capability of the carbon canister;

[0056] S5. Calculate the degradation rate of the oil and gas recovery system's working capacity based on the bench test data of new and old vehicles and the proportional coefficient.

[0057] The proportionality coefficient in S1 is calculated based on the contribution of permeation emissions and carbon canister escape emissions to the annual evaporative emissions of the vehicle. The anti-permeability coefficient K p , Carbon canister working capacity coefficient K f Specifically:

[0058]

[0059] Where: M p (g / day) is the average daily permeation emission of the fuel system, α is the average annual breakdown number of the carbon canister, M f (g) is the average emission from each carbon canister breakdown, β is the average annual number of refueling times for the vehicle, M r (g) The average emission from the charcoal canister during each refueling.

[0060] The S2 is specifically:

[0061] S21. The test vehicle pushes the evaporation tank of the whole vehicle, the fuel tank is drained, and the refueling equipment is filled with 40% of the nominal volume of the fuel tank;

[0062] S22, connecting the atmospheric port of the carbon canister to a long air pipe, and connecting the other end of the long air pipe to an auxiliary carbon canister placed outside the bin;

[0063] S23, the evaporation chamber is turned on for a day and night temperature cycle, and the concentration of hydrocarbons in the evaporation chamber before and after the test is monitored by a hydrogen flame ionization detector. The calculation results are converted into vehicle background and permeation emissions, recorded as M total (g);

[0064] S24, use a vacuum pump to drain the fuel in the fuel tank, let it stand for a while, repeat S22 and S23, and convert the calculation result into the background emission of the non-fuel system of the whole vehicle, recorded as M background (g);

[0065] The conversion calculation method is as follows:

[0066]

[0067] Where: M(g) is the emission; V is the net volume of the closed room corrected by the volume of the car (windows and trunk open). If the volume of the car is not determined, subtract 1.42m 3 ; k is 1.2*(12+H / C); C HC (ppm) is the hydrocarbon concentration in the closed room; P (kPa) is the atmospheric pressure; T 24 (K) is the ambient temperature of the sealed room after one day and night; i represents the initial reading; M HC，出 (g) is the mass of hydrocarbons discharged from a closed chamber of constant volume when a hot soak or day and night ventilation test is carried out in the closed chamber of constant volume; M HC，入(g) The mass of hydrocarbons entering a closed chamber of constant volume when the chamber is used for heat soak or day and night ventilation test;

[0068] M total (g) and M background (g) The corresponding results can be obtained through the above conversion calculation method;

[0069] S25, M total With M background The difference is the anti-permeability capacity W of the new car oil and gas recovery system p1 (g / test);

[0070] In S3, the working capacity of the carbon canister is divided into the refueling working capacity W r (g / L) and diurnal respiratory work capacity W b (g / L), and determine the proportionality coefficient based on the bench test results. The specific test method is as follows:

[0071] S31. Charcoal canister refueling capacity test: disconnect the charcoal canister from the fuel tank, connect the charcoal canister adsorption port to the loading port of the oil and gas loading device, connect one end of the long gas pipe to the charcoal canister atmospheric port, and the other end to the micro evaporation chamber. Before the test, the oil and gas loading device desorbs 600BV of the charcoal canister, and then the oil and gas loading device loads the charcoal canister at a rate of 2700g / h. When the mass increment of hydrocarbons in the micro evaporation chamber exceeds 50mg, stop loading. The ratio of the total loading amount to the charcoal canister volume is the initial charcoal canister refueling capacity W r1 ;

[0072] S32, carbon canister day and night breathing capacity test: During the test, the oil and gas loading equipment loads the carbon canister at a rate of 2.5g / h. The other steps are the same as S31. The ratio of the total loading amount to the carbon canister volume is the initial carbon canister day and night breathing capacity W b1 ;

[0073] S33, carbon canister refueling capacity ratio coefficient K r The ratio coefficient K of the day and night breathing capacity of the charcoal canister b They are:

[0074]

[0075] Where: W b1 W is the initial charcoal canister's day and night breathing capacity; r1 Refueling capacity for initial canister.

[0076] In S4, the test method for the old car is the same as that for the new car, and the test result of the anti-penetration ability of the old car is recorded as W p2 , the charcoal canister refueling capacity test result is recorded as W r2 , the test result of the day and night breathing capacity of the degraded carbon canister is recorded as Wb2 ;

[0077] The oil and gas recovery system working capacity degradation rate in S5 The calculation method is:

[0078]

[0079] Where: W p1 W is the initial canister anti-permeability capability; p2 To degrade the anti-permeability capability of the carbon canister; b2 To degrade the day and night breathing capacity of the carbon canister; r2 Deterioration of the refueling capacity of the carbon canister; K p K is the anti-penetration coefficient; f K is the working capacity coefficient of the carbon canister; r Refueling capacity ratio coefficient for charcoal canister; K b It is the ratio coefficient of the day and night breathing capacity of the carbon canister.

[0080] like Figure 2 As shown, a device for implementing the vehicle oil and gas recovery system working capacity degradation rate test method includes: a vehicle evaporation chamber 1, a miniature evaporation chamber 2, a hydrogen flame ionization detector 3, a refueling device 4, a vacuum pump 5, a long gas pipe 6, an oil and gas loading device 7, and an auxiliary carbon canister 8;

[0081] The whole vehicle evaporation chamber 1 and the miniature evaporation chamber 2 are equipped with a hydrogen flame ionization detector 3;

[0082] The refueling equipment 4, vacuum pump 5, oil and gas loading equipment 7, and auxiliary carbon canister 8 are all installed outside the evaporation chamber;

[0083] The refueling device 4 is connected to the fuel tank of the test vehicle in the evaporation chamber 1 of the whole vehicle when the vehicle is refueled;

[0084] The vacuum pump 5 is connected to the fuel tank of the test vehicle in the vehicle evaporation bin 1 to pump oil when conducting the non-fuel system evaporative emission test;

[0085] The long air pipe 6 is connected to the atmospheric port of the test vehicle canister and the micro evaporation chamber 2 when testing day and night breathing emissions;

[0086] The long air pipe 6 is connected to the atmospheric port of the vehicle carbon canister and the adsorption port of the auxiliary carbon canister 8 when testing the permeation emission.

[0087] It can be connected to the micro evaporation chamber 2, the auxiliary carbon canister 8 adsorption port, and the atmospheric port of the test vehicle carbon canister in the whole vehicle evaporation chamber 1;

[0088] The oil and gas loading device 7 is connected to the vehicle canister desorption port of the test vehicle in the vehicle evaporation bin 1 before the experiment to perform desorption before the experiment;

[0089] The oil and gas loading device 7 is connected to the adsorption port of the test vehicle carbon canister in the evaporation bin 1 of the whole vehicle when the carbon canister refueling working capacity test is performed.

[0090] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0091] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for testing the degradation rate of working capacity of a vehicle oil and gas recovery system, characterized in that: The steps include: S1. The working capacity of the oil and gas recovery system is divided into the anti-permeability capacity and the carbon canister working capacity, and a proportional coefficient is assigned; S2. The bench test begins, and the anti-penetration capability test of the oil and gas recovery system of the new vehicle is carried out; S3. Test the working capacity of the carbon canister of the oil and gas recovery system of the new car, including the refueling working capacity of the carbon canister and the day and night breathing working capacity of the carbon canister, and determine the proportional coefficient of the two based on the test results; S4. Test the anti-penetration capability of the oil and gas recovery system of the old car and the working capability of the carbon canister; S5. Calculate the degradation rate of the oil and gas recovery system's working capacity based on the bench test data of new and old vehicles and the proportional coefficient.

2. A vehicle oil and gas recovery system working capacity degradation rate testing method according to claim 1, characterized in that: The proportionality coefficient in S1 is calculated based on the contribution of permeation emissions and carbon canister escape emissions to the annual evaporative emissions of the vehicle. The anti-permeability coefficient K p , Carbon canister working capacity coefficient K f Specifically: Where: M p (g / day) is the average daily permeation emission of the fuel system, α is the average annual breakdown number of the carbon canister, M f (g) is the average emission from each carbon canister breakdown, β is the average annual number of refueling times for the vehicle, M r (g) The average emission from the charcoal canister during each refueling.

3. A vehicle oil and gas recovery system working capacity degradation rate testing method according to claim 1, characterized in that: The S2 is specifically: S21. The test vehicle pushes the evaporation tank of the whole vehicle, the fuel tank is drained, and the refueling equipment is filled with 40% of the nominal volume of the fuel tank; S22, connecting the atmospheric port of the carbon canister to a long air pipe, and connecting the other end of the long air pipe to an auxiliary carbon canister placed outside the bin; S23, the evaporation chamber is turned on for a day and night temperature cycle, and the concentration of hydrocarbons in the evaporation chamber before and after the test is monitored by a hydrogen flame ionization detector. The calculation results are converted into vehicle background and permeation emissions, recorded as M total (g); S24, use a vacuum pump to drain the fuel in the fuel tank, let it stand for a while, repeat S22 and S23, and convert the calculation result into the background emission of the non-fuel system of the whole vehicle, recorded as M background (g); The conversion calculation method is as follows: Where: M(g) is the emission; V is the net volume of the closed room after correction for the vehicle volume (windows and trunk open). If the vehicle volume is not determined, subtract 1.42m 3 ; k is 1.2*(12+H / C); C HC (ppm) is the hydrocarbon concentration in the closed room; P (kPa) is the atmospheric pressure; T 24 (K) is the ambient temperature of the sealed room after one day and night; i represents the initial reading; M HC，出 (g) is the mass of hydrocarbons discharged from a closed chamber of constant volume when a hot soak or day and night ventilation test is carried out in the closed chamber of constant volume; M HC，入 (g) The mass of hydrocarbons entering a closed chamber of constant volume when the chamber is used for heat soak or day and night ventilation test; S25, M total With M background The difference is the anti-permeability capacity W of the new car oil and gas recovery system p1 (g / test).

4. A vehicle oil vapor recovery system working capacity degradation rate testing method according to claim 1, characterized in that: In S3, the working capacity of the carbon canister is divided into the refueling working capacity W r (g / L) and diurnal respiratory work capacity W b (g / L), and determine the proportionality coefficient based on the bench test results. The specific test method is as follows: S31. Charcoal canister refueling capacity test: disconnect the charcoal canister from the fuel tank, connect the charcoal canister adsorption port to the loading port of the oil and gas loading device, connect one end of the long gas pipe to the charcoal canister atmospheric port, and the other end to the micro evaporation chamber. Before the test, the oil and gas loading device desorbs 600BV of the charcoal canister, and then the oil and gas loading device loads the charcoal canister at a rate of 2700g / h. When the mass increment of hydrocarbons in the micro evaporation chamber exceeds 50mg, stop loading. The ratio of the total loading amount to the charcoal canister volume is the initial charcoal canister refueling capacity W r1 ; S32, carbon canister day and night breathing capacity test: During the test, the oil and gas loading equipment loads the carbon canister at a rate of 2.5g / h. The other steps are the same as S31. The ratio of the total loading amount to the carbon canister volume is the initial carbon canister day and night breathing capacity W b1 ; S33, carbon canister refueling capacity ratio coefficient K r The ratio coefficient K of the day and night breathing capacity of the charcoal canister b They are: Where: W b1 W is the initial canister's day and night breathing capacity; r1 Refueling capacity for initial canister.

5. The method for testing the degradation rate of working capacity of a vehicle oil vapor recovery system according to claim 1, characterized in that: In S4, the test method for the old car is the same as that for the new car, and the test result of the anti-penetration ability of the old car is recorded as W p2 , the charcoal canister refueling capacity test result is recorded as W r2 The test result of the day and night breathing capacity of the degraded carbon canister is recorded as W b2。 6. A vehicle oil vapor recovery system working capacity degradation rate testing method according to claim 1, characterized in that: The oil and gas recovery system working capacity degradation rate in S5 The calculation method is: Where: W p1 W is the initial canister anti-permeability capability; p2 To degrade the anti-permeability capability of the carbon canister; b2 To degrade the day and night breathing capacity of the carbon canister; r2 Deterioration of the refueling capacity of the carbon canister; K p K is the anti-penetration coefficient; f K is the working capacity coefficient of the carbon canister; r Refueling capacity ratio coefficient for charcoal canister; K b It is the ratio coefficient of the day and night breathing capacity of the carbon canister.

7. A device for implementing the vehicle oil vapor recovery system working capacity degradation rate testing method described in claims 1-6, characterized in that: include: A whole vehicle evaporation chamber (1), a miniature evaporation chamber (2), a hydrogen flame ionization detector (3), a refueling device (4), a vacuum pump (5), a long gas pipe (6), an oil and gas loading device (7), and an auxiliary carbon canister (8); The whole vehicle evaporation chamber (1) and the micro evaporation chamber (2) are equipped with a hydrogen flame ionization detector (3); The refueling equipment (4), vacuum pump (5), oil and gas loading equipment (7), and auxiliary carbon canister (8) are all installed outside the evaporation chamber; The refueling device (4) is connected to the fuel tank of the test vehicle in the evaporation chamber (1) of the whole vehicle when the vehicle is refueled; The vacuum pump (5) is connected to the fuel tank of the test vehicle in the vehicle evaporation bin (1) to pump oil when conducting a non-fuel system evaporative emission test; The long air pipe (6) is connected to the atmospheric port of the carbon canister of the test vehicle and the micro evaporation chamber (2) when testing daytime and nighttime respiratory emissions; The long air pipe (6) is connected to the atmospheric port of the vehicle carbon canister and the adsorption port of the auxiliary carbon canister (8) when testing the permeation emission. It can be connected to the micro evaporation chamber (2), the adsorption port of the auxiliary carbon canister (8), and the atmospheric port of the carbon canister of the test vehicle in the evaporation chamber (1); The oil and gas loading device (7) is connected to the vehicle carbon canister desorption port of the test vehicle in the whole vehicle evaporation bin (1) before the experiment to perform desorption before the experiment; When testing the refueling capacity of the carbon canister, the oil and gas loading device (7) is connected to the adsorption port of the carbon canister of the test vehicle in the evaporation bin (1) of the whole vehicle.

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