Cyclic sampling device and sampling method for canister bleed evaporative emission sealed chamber

Abstract

The present invention relates to the technical field of devices for testing motor vehicle emission sources. Disclosed are a cyclic sampling device and sampling method for a canister bleed evaporative emission sealed chamber. The cyclic sampling device comprises a canister bleed evaporative emission sealed chamber (2), a pipe assembly (10) and a gas pump (5); an SV1 solenoid valve and an SV2 solenoid valve are provided between the canister bleed evaporative emission sealed chamber (2) and a canister (1); the gas pump (5) is arranged between the SV1 solenoid valve and the canister bleed evaporative emission sealed chamber (2); the SV2 solenoid valve enables a gas to circulate in the canister bleed evaporative emission sealed chamber (2) and the pipe assembly (10), and the SV1 solenoid valve enables the gas to circulate between the canister bleed evaporative emission sealed chamber (2) and the canister (1). By controlling the SV2 solenoid valve, turning off the SV1 solenoid valve and turning on the gas pump (5), a residual gas can circulate between a pipe and the canister bleed evaporative emission sealed chamber (2), thereby preventing the residual gas in the pipe from affecting the stability of measurement.

Description

A carbon canister emission evaporation closed chamber circulation sampling device and sampling method Technical Field

[0001] This invention relates to the field of motor vehicle emission source testing equipment technology, specifically to a carbon canister emission evaporation closed chamber circulation sampling device and sampling method. Background Technology

[0002] Currently, closed evaporative emission chambers are commonly used to test hydrocarbon emissions from vehicles. These chambers simulate various environmental conditions encountered during actual vehicle use, such as different temperatures, humidity levels, and air pressures. This allows for more accurate detection of hydrocarbon emissions during real-world operation, avoiding interference from external factors encountered during testing in open environments.

[0003] Application No. 202322282124.0 discloses a detection method for detecting hydrocarbon emissions in vehicles using an evaporative emission chamber and its vehicle test chamber, which can make the gas distribution in the evaporative emission chamber and the vehicle comprehensive environmental test chamber more uniform.

[0004] However, during the implementation of the aforementioned evaporation sealed chamber and its vehicle test chamber, residual gas from the emission process may remain in the gas pipeline. Since some gas remains in the gas pipeline, the data detected during the actual testing process will have certain errors. In order to make the detected values ​​accurate and stable, this invention provides a novel testing device and sampling method. Summary of the Invention

[0005] The purpose of this invention is to provide a carbon canister emission evaporation closed chamber circulation sampling device and sampling method to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a carbon canister emission recycling sampling device, comprising:

[0007] Carbon canister escape emission evaporation sealed chamber 2, piping assembly 10, circulation pump 5;

[0008] An SV1 solenoid valve and an SV2 solenoid valve are installed between the carbon canister evaporation and evaporation sealed chamber 2 and the carbon canister 1. A circulation pump 5 is installed between the SV1 solenoid valve and the carbon canister evaporation and evaporation sealed chamber 2. The SV2 solenoid valve allows the gas to circulate within the carbon canister evaporation and evaporation sealed chamber 2 and the pipeline assembly 10. The SV1 solenoid valve allows the gas to circulate between the carbon canister evaporation and evaporation sealed chamber 2 and the carbon canister 1. The pipeline assembly 10 and the SV1 solenoid valve are located in the main evaporation sealed chamber 4.

[0009] Furthermore, regarding this scheme, the carbon canister escape emission evaporation sealed chamber 2 is equipped with a gas bag 3, and the gas bag 3 is externally connected to a gas supply system, which includes:

[0010] Pressure reducing valve, mass flow valve FV1, V1 solenoid valve, V3 solenoid valve, and positive and negative pressure sensors 9;

[0011] One end of the pressure reducing valve is connected to a gas source, and one end of the V3 solenoid valve is connected to the atmospheric balance port of the gas bag. The pressure reducing valve and the V3 solenoid valve are connected to the gas bag 3 through a single gas passage. The mass flow valve FV1, the V1 solenoid valve, and the positive and negative pressure sensor 9 are installed sequentially on the single gas passage. The positive and negative pressure sensor 9 is also connected to the V3 solenoid valve by a V2 solenoid valve, and the mass flow valve FV2 is installed at the V2 solenoid valve.

[0012] Furthermore, the gas bag 3 is equipped with a butterfly breathing valve, which is connected to the external air pressure through the atmospheric balance port of the gas bag. The gas bag 3 interacts with the external gas through the butterfly breathing valve, thereby maintaining the air pressure balance of the carbon canister evaporation and evaporation sealed chamber 2.

[0013] A carbon canister emission recycling sampling method, wherein the aforementioned carbon canister emission recycling sampling equipment includes the following steps:

[0014] Step 1: Connect carbon canister 1 to the carbon canister exhaust evaporation sealed chamber, and simulate the day and night changes in the ambient temperature of the car when it is parked by changing the ambient temperature inside the sealed chamber.

[0015] Step 2: Evacuate the gas bag 3 in the carbon canister evacuation and emission sealed chamber 2, and then inflate the gas bag 3 to make the volume inside the chamber reach the specified volume.

[0016] Step 3: During the process of evacuating and inflating the air bag 3 to maintain the balance inside the chamber, open the balance valve inside the chamber, close the carbon canister evaporation evaporation sealed chamber 2, and perform initial sampling inside the carbon canister evaporation evaporation sealed chamber 2, record the data, and at the same time open the SV2 solenoid valve. Then, conduct the emission test of carbon canister 1, and set an appropriate detection time of 24h-72h according to customer needs.

[0017] Step 4: 1 minute before the carbon canister 1 emission test reaches 24h-72h, close the SV2 solenoid valve, open the SV1 solenoid valve and start the gas pump 5 to make the hydrocarbon waste gas circulate between the pipeline and the carbon canister emission evaporation sealed chamber 2 for 1 minute-10 minutes before final sampling.

[0018] Furthermore, the carbon canister is equipped with a V4 solenoid valve to maintain the balance inside the chamber, and a V5 sampling valve and a V6 return sampling valve to control the entry and exit of the HFID calibration gas, respectively.

[0019] The carbon canister evaporation and evaporation sealed chamber 2 is also equipped with a temperature sensor 8 and a differential pressure sensor 7, and a fan 6 is installed inside the carbon canister evaporation and evaporation sealed chamber 2.

[0020] The carbon canister evaporation and evaporation sealed chamber 2 is also equipped with a propane injection port and a sampling pipeline assembly connection port.

[0021] Further, step two of the plan, which involves evacuating air bag 3, includes the following steps:

[0022] S1: Solenoid valves V1 and V3 are closed, with a delay of 10 seconds;

[0023] S2: Open V4 solenoid valve, delay for 2 seconds;

[0024] S3: Turn on the V2 solenoid valve and the FV air pump, and make a judgment;

[0025] If the differential pressure sensor 7 is less than or equal to -3kp within 10 minutes after the V2 solenoid valve is opened, the V2 solenoid valve is closed and then the V4 solenoid valve is closed after a 2-second delay.

[0026] If the differential pressure sensor 7 detects that the pressure in the sealed evaporation chamber of the carbon canister is greater than -3 kp within 10 minutes after the V2 solenoid valve is opened, it will alarm and shut down, and automatically close the V2 solenoid valve. Then, after a 2-second delay, the V4 solenoid valve will be closed.

[0027] Further, inflating the air bag 3 in step two includes the following steps:

[0028] A1: Confirm that solenoid valve V2 is in the closed position;

[0029] A2: Confirm that V3 is in the off state;

[0030] A3: Open solenoid valve V1;

[0031] A4: After a 2-second delay, open the mass flow valve FV1, inject gas into the gas bag 3, and then make a judgment.

[0032] A5: After inflation is complete, close the mass flow valve FV1 and then close the solenoid valve V1 after a 2-second delay.

[0033] Further, step three of the sampling process inside the cabin includes the following steps:

[0034] V1: Check whether the storage volume of zero gas, hydrogen-nitrogen mixture, and standard gas is sufficient;

[0035] V2: HFID power on;

[0036] V3: Enter the standard gas concentration and confirm the sampling range;

[0037] V4: HFID automatic calibration;

[0038] V5: Carbon canister escape emission evaporation sealed chamber 2 sampling: Close V4 and sample balance valve, and open V5 sampling valve and V6 return sampling valve at the same time;

[0039] V6: Sample for 2 minutes, take the value 0.1 seconds before the end, and sample once per hour;

[0040] V7: Standby.

[0041] To further elaborate on this scheme, step one, simulating changes in ambient temperature, includes the following steps:

[0042] Q1: Confirm that solenoid valves V3 and V4 are in the closed state;

[0043] Q2: Turn on fan 6;

[0044] Q3: Raise the temperature inside the sealed evaporation chamber 2 of the carbon canister to 10℃-70℃;

[0045] Q4: Air bag 3 is evacuated and the process is complete; then air bag 3 is inflated and the process is complete, and HFID is automatically calibrated.

[0046] Q5: Open the V3 solenoid valve and the air bag 3 vent valve;

[0047] Q6: After a 2-second delay, the test timing will begin;

[0048] Q7: Initial sampling, record sampling data, including sampling time, sampling temperature, sampling absolute pressure, sampling concentration (ppmc1), sampling mass concentration, and mass concentration difference;

[0049] Q8: Set HFID to automatically calibrate 6 minutes before the hour arrives;

[0050] Q9: Set the final sampling to be performed 2 minutes before the hour arrives, sample for 2 minutes and record the data;

[0051] Q10: True or False;

[0052] Q11: The V3 solenoid valve is closed, and the test is over.

[0053] Compared with the prior art, the beneficial effects of the present invention are:

[0054] This carbon canister emission evaporation sealed chamber circulation sampling device and sampling method controls the flow of hydrocarbons between the carbon canister and the carbon canister emission evaporation sealed chamber by controlling the SV1 solenoid valve, and detects the concentration of hydrocarbons. By controlling the SV2 solenoid valve and closing the SV1 solenoid valve, the flow of residual hydrocarbons between the pipeline and the carbon canister emission evaporation sealed chamber can be controlled, avoiding the influence of residual gas in the pipeline on the stability of the detection in the carbon canister emission evaporation sealed chamber, making the detected values ​​stable, and ensuring the accuracy of the test.

[0055] Meanwhile, by controlling the volume of the gas bag, the balance of the carbon canister's emission and evaporation in the sealed chamber is maintained. A butterfly breathing valve is installed inside the gas bag, which is connected to the external air pressure through the gas bag's atmospheric balance port. The gas bag interacts with the external gas through the butterfly breathing valve, thereby maintaining the air pressure balance of the carbon canister's emission and evaporation in the sealed chamber, making the test results less susceptible to changes in temperature and pressure. Attached Figure Description

[0056] Figure 1 is a schematic diagram of the process of the carbon canister escape emission evaporation closed chamber circulation sampling method of the present invention;

[0057] Figure 2 is a schematic diagram of the carbon canister escape emission evaporation sealed chamber circulation sampling device of the present invention;

[0058] Figure 3 is a schematic diagram of the carbon canister escape emission evaporation sealed chamber extraction process of the present invention.

[0059] Figure 4 is a schematic diagram of the carbon canister escape emission evaporation sealed chamber gas filling process of the present invention.

[0060] Figure 5 is a schematic diagram of the sampling process of the present invention;

[0061] Figure 6 is a schematic diagram of the day-night alternation test method of the present invention.

[0062] In the diagram: 1. Carbon canister; 2. Carbon canister evaporation and sealing chamber; 3. Air bag; 4. Vehicle evaporation and sealing chamber; 5. Air pump; 6. Fan; 7. Differential pressure sensor; 8. Temperature sensor; 9. Positive and negative pressure sensors; 10. Piping assembly. Detailed Implementation

[0063] 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.

[0064] The following points should be noted in this embodiment:

[0065] Zero gas is a gas that is calibrated to zero. It can be zeroed using pure air and has a reference value of zero.

[0066] HFID automatic calibration refers to the automatic calibration function used when using a flame ionization detector (HFID) to ensure the accuracy and stability of the detector. HFID automatic calibration typically includes the following steps and precautions:

[0067] 1. Automatic Calibration Function: HFID detectors typically feature an automatic calibration function, which can automatically calibrate during the testing process, reducing manual intervention and maintenance costs. This function uses a built-in calibration program to periodically calibrate the detector, ensuring stable performance.

[0068] 2. Calibration gas: Methane is commonly used as the calibration gas in HFID because it has a high response. During calibration, a known concentration of methane gas is injected, and the detector will output a corresponding signal. By comparing the actual signal with the theoretical signal, the sensitivity and response range of the detector can be adjusted to ensure its accuracy.

[0069] 3. Calibration Cycle: The calibration cycle can be set based on the usage frequency and detector stability. Generally, it is recommended to perform automatic calibration daily or after a period of use to ensure that the detector's performance does not change due to prolonged use.1

[0070] 4. Maintenance and Troubleshooting: During automatic calibration, it is necessary to ensure the cleanliness and unobstructed flow of the gas system, and to ensure the correct flow ratio of hydrogen, carrier gas, and air. Common faults include failure to ignite, excessive base current, and excessive noise. These problems can be resolved by checking the gas system and adjusting the detector parameters.

[0071] By following the steps and methods above, the automatic calibration of HFID can be effectively achieved, ensuring its accuracy and stability during use.

[0072] As shown in Figure 1, the present invention provides a technical solution: a circulating sampling device for a carbon canister emission evaporation sealed chamber 2, comprising a carbon canister emission evaporation sealed chamber 2 and a carbon canister 1. An SV1 solenoid valve and an SV2 solenoid valve are provided between the carbon canister emission evaporation sealed chamber 2 and the carbon canister 1. An air pump 5 is provided between the SV1 solenoid valve and the carbon canister emission evaporation sealed chamber 2. By controlling the opening and closing of the SV2 solenoid valve, the gas can be controlled to circulate between the carbon canister emission evaporation sealed chamber 2 and the pipeline assembly 10 connected to the SV2 solenoid valve. The SV1 solenoid valve allows the gas to circulate between the carbon canister emission evaporation sealed chamber 2 and the carbon canister 1. The sampling device is placed inside the vehicle evaporation sealed chamber 4.

[0073] By controlling the SV1 solenoid valve, the flow of hydrocarbons between the carbon canister 1 and the carbon canister emission evaporation sealed chamber 2 can be controlled, and the concentration of hydrocarbons can be detected. By controlling the SV2 solenoid valve, the SV1 solenoid valve is closed, and the gas pump 5 is turned on, allowing the residual hydrocarbons to flow between the pipeline and the carbon canister emission evaporation sealed chamber 2. This prevents the residual gas in the pipeline from affecting the stability of the detection in the carbon canister emission evaporation sealed chamber 2, making the detected values ​​stable and ensuring the accuracy of the test.

[0074] As shown in Figure 2, the sealed evaporation chamber 2 of the carbon canister contains a gas bag 3, and the gas bag 3 is connected to a gas supply system, which includes:

[0075] Pressure reducing valve, mass flow valve FV1, solenoid valve V1, solenoid valve V3, and positive and negative pressure sensors;

[0076] One end of the pressure reducing valve is connected to a gas source, and one end of the V3 solenoid valve is connected to the atmospheric balance port of the gas bag. The pressure reducing valve and the V3 solenoid valve are connected to the gas bag 3 through a single gas passage. The mass flow valve FV1, the V1 solenoid valve, and the positive and negative pressure sensors are installed sequentially on the single gas passage. The positive and negative pressure sensors are also connected to the V3 solenoid valve by a V2 solenoid valve, and the mass flow valve FV2 is installed at the V2 solenoid valve.

[0077] The carbon canister emission evaporation sealed chamber 2 of the circulating sampling device is equipped with a V4 solenoid valve for maintaining the balance inside the chamber, and a V5 sampling valve and a V6 return sampling valve for controlling the inlet and outlet of HFID calibration gas for gas concentration detection. The carbon canister emission evaporation sealed chamber 2 is also equipped with a positive and negative pressure sensor 9, a differential pressure sensor 7, and a propane injection port. The vent hole of the propane injection port is connected to the sample, and a sample balance valve is installed at the sample.

[0078] The pressure balance inside the chamber is maintained by setting up an air bag 3. One end of the V1 solenoid valve is used to inflate the air bag 3, and the other end of the V2 solenoid valve is used to evacuate the air bag 3. By controlling the volume of the air bag 3, the balance inside the carbon canister emission evaporation sealed chamber 2 is maintained. A butterfly breather valve is installed inside the air bag 3. The butterfly breather valve is connected to the external air pressure through the atmospheric balance port of the air bag. The air bag 3 interacts with the external gas through the butterfly breather valve, thereby maintaining the pressure balance inside the carbon canister emission evaporation sealed chamber 2. This makes the test results less susceptible to the influence of temperature and pressure changes. Sampling and detection are carried out at the V4 solenoid valve and the propane injection port. The V5 sampling valve is mainly used to control the collection process of exhaust gas sample. During detection, opening the V5 sampling valve allows the hydrocarbon exhaust gas emitted by the vehicle to enter the sampling pipeline of the detection system. The V6 return sampling valve returns the detected hydrocarbon exhaust gas to the carbon canister emission evaporation sealed chamber 2 to maintain the pressure balance inside the chamber. The gas concentration inside the chamber is detected by the V5 sampling valve and the V6 return sampling valve.

[0079] As shown in Figure 2, for the above-mentioned equipment, we provide a circulating sampling method for the carbon canister emission evaporation closed chamber, which specifically includes the following steps:

[0080] Step 1: Connect carbon canister 1 to carbon canister evaporation and evaporation sealed chamber 2, and simulate the day and night changes in ambient temperature when the car is parked by changing the ambient temperature inside the chamber.

[0081] Step 2: Evacuate the gas bag 3 in the carbon canister evacuation and emission sealed chamber 2, and then inflate the gas bag 3 to make the chamber volume reach the specified volume.

[0082] Step 3: During the process of evacuating and inflating the air bag 3 to maintain the balance inside the chamber, open the balance valve inside the chamber and take initial samples of the carbon canister evaporation and emission in the sealed evaporation chamber 2, record the data, and then conduct the evaporation emission experiment of the carbon canister 1. The detection time is 24h-72h.

[0083] Step 4: Open the SV2 solenoid valve during the 24-72 hour test of carbon canister 1;

[0084] Step 5: During the 24-72 hours of testing in carbon canister 1, sampling is performed once every hour. When sampling, the SV2 solenoid valve is closed, the SV1 solenoid valve is opened, and the gas pump 5 is started to circulate the hydrocarbon waste gas between the pipeline and the carbon canister's emission evaporation sealed chamber 2 for 1-10 minutes before final sampling.

[0085] We confirmed the above cyclic sampling method through the following experiment:

[0086] Example 1: Testing the impact of the carbon canister vent connection pipeline on BETP results;

[0087] Sample requirements: Same fuel system and charcoal canister; nylon tubing with inner diameters of 4mm, 6.5mm, and 8mm, and a length of 4m;

[0088] Test 1

[0089] Test Results

[0090] Analysis: Despite very low airflow resistance, a significant difference in emissions still occurred, with overall emissions being lower than expected. It is speculated that the pipe material adsorbs hydrocarbon waste gas or leaves hydrocarbon waste gas residue. Test 2 was conducted by changing the pipe material to test the impact of the pipe material on the BETP results.

[0091] Sample requirements: Same fuel system and charcoal canister; PTFE tubing with inner diameters of 4mm, 6.5mm, and 8mm and a length of 4m.

[0092] Test 2

[0093] Test Results

[0094] Analysis: Using PTFE pipes can slightly reduce the adhesion of hydrocarbon waste gas substances, but the deposition problem still cannot be solved, resulting in a large deviation from the actual situation. It is considered to purge the gas in the pipes to confirm the impact of residual gas in the pipes on the test results.

[0095] Sample requirements: Same fuel system and charcoal canister; PTFE tubing with inner diameters of 4mm, 6.5mm, and 8mm, and a length of 4m;

[0096] Test 3

[0097] Test Results

[0098] Analysis: After being purged by airflow and fully mixed, the measured value of the carbon canister's exhaust emission is consistent with the measured value of "no pipeline". It can be seen that the residual hydrocarbon waste gas in the pipeline between carbon canister 1 and carbon canister overflow emission chamber 2 has a significant impact on the detection of carbon canister 1.

[0099] As shown in Figure 3, in step two of the circulating sampling method of the carbon canister emission evaporation sealed chamber 2, evacuating the gas bag 3 requires confirming that solenoid valves V1 and V3 are closed. Because solenoid valves V1 and V3 are closed, the pressure sensor 9 may have inaccurate readings during the pumping process. To avoid air stagnation (when the pressure sensor reading is low while the actual pressure is continuously increasing, the pumping system may continue to work without stopping, causing the pressure inside the system to gradually increase; once it reaches a certain level, the gas cannot be smoothly extracted), the system may experience air stagnation. (If a shortness of breath occurs), the V4 solenoid valve needs to be opened after a 10-second delay, and the V2 solenoid valve needs to be opened after another 2-second delay. The following judgments are made: If the differential pressure sensor 7 is less than or equal to -3 kp within 10 minutes after the V2 solenoid valve is opened, the V2 solenoid valve is closed and then the V4 solenoid valve is closed after a 2-second delay. If the differential pressure sensor 7 detects that the pressure in the sealed chamber where the carbon canister is evacuated and evaporates is greater than -3 kp within 10 minutes after the V2 solenoid valve is opened, an alarm is triggered and the machine is stopped, indicating that the air bag 3 is not completely evacuated. The V2 solenoid valve is automatically closed, and the V4 solenoid valve is closed after a 2-second delay.

[0100] As shown in Figure 4, in step two of the cyclic sampling method of carbon canister emission evaporation sealed chamber 2, it is necessary to confirm that solenoid valve V2 is closed before filling gas bag 3, and then confirm that solenoid valve V3 is closed. After that, solenoid valve V1 is opened, and mass flow valve FV1 is opened after a 2-second delay. Gas is injected into gas bag 3 and then a judgment is made. When the filling is completed, mass flow valve FV1 is closed, and solenoid valve V1 is closed after a 2-second delay.

[0101] Regarding the inflation and deflation of air bag 3, it is important to know that the compressed air source connected to the inflation connection controls the inflation of air bag 3 through a flow meter. This ensures stable air source pressure and facilitates the calculation of gas flow through the flow meter. All inflation and deflation use two independent systems to ensure stable air source pressure.

[0102] In summary, after the carbon canister 1 test is completed, the SV2 solenoid valve is closed and the SV1 solenoid valve is opened. The air pump 5 starts working, which circulates the residual gas in the carbon canister evaporation evaporation sealed chamber and the pipeline connected to carbon canister 1. When the residual gas concentration is detected in the carbon canister evaporation evaporation sealed chamber, the detected value is stable, ensuring the accuracy of the test.

[0103] As shown in Figure 5, sampling within the sealed evaporation chamber 2 of the carbon canister exhaust emission includes the following steps:

[0104] Step 1: Check whether the storage quantities of zero gas, hydrogen-nitrogen mixture, and standard gas are sufficient;

[0105] Step 2: Power on HFID;

[0106] Step 3: Enter the standard gas concentration and confirm the sampling range;

[0107] Step 4: Automatic HFID calibration;

[0108] Step 5: Sample the carbon canister evaporation evaporation sealed chamber 2, close the V4 solenoid valve and sample balance valve, and simultaneously open the V5 sampling valve and the V6 return sampling valve. The V5 sampling valve and the V6 return sampling valve must be opened at the same time to ensure that the pressure inside the chamber remains constant during the HFID gas detection process.

[0109] Step Six: Sample for 2 minutes, taking the value 0.1 seconds before the end. The sampling frequency is once per hour, ensuring that each cabin is sampled independently and there is no interference between cabins.

[0110] Step 7: Standby.

[0111] As shown in Figure 6, the diurnal variation of ambient temperature when a car is parked is simulated using a day-night alternation test method, which includes the following steps:

[0112] Step 1: Confirm that solenoid valves V3 and V4 are in the closed state;

[0113] Step 2: Turn on fan 6 to allow hydrocarbon gas to circulate in the cabin and reduce uneven distribution of hydrocarbons in the cabin.

[0114] Step 3: Raise the temperature inside the carbon canister evaporation and sealing chamber 2 to 10℃-70℃ (preset according to requirements);

[0115] Step 4: De-air the air bag 3 and complete the process;

[0116] Step 5: Once the cabin temperature reaches 10℃-70℃ (preset temperature), inflate air bag 3 and complete the process; HFID will automatically calibrate.

[0117] Step 6: Open the V3 solenoid valve;

[0118] Step 7: After a 2-second delay, the test timing begins;

[0119] Step 8: Sampling for the 0th time. The initial state inside the chamber is sampled. The sampling data includes sampling time, sampling temperature, sampling absolute pressure, sampling concentration (ppmc1), sampling mass concentration, and mass concentration difference.

[0120] Step 9: Sample and record the data every hour;

[0121] Step 10: Automatic HFID calibration for the first 6 minutes of the 24-hour period;

[0122] Step 11: Perform the 24th sampling 2 minutes before the 24-hour mark, sample for 2 minutes and record the data;

[0123] Step 12: Judgment; judgment is performed on the sampled data from Step 9 respectively;

[0124] Step 13: Close solenoid valve V3; test complete.

[0125] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended embodiments and their equivalents.

Claims

1. A carbon canister emission recycling sampling device, characterized in that, include: Carbon canister escape emission evaporation sealed chamber (2), pipeline assembly (10), circulation pump (5); An SV1 solenoid valve and an SV2 solenoid valve are provided between the carbon canister evaporation and evaporation sealed chamber (2) and the carbon canister (1). A circulation pump (5) is provided between the SV1 solenoid valve and the carbon canister evaporation and evaporation sealed chamber (2). The SV2 solenoid valve allows the gas to circulate within the carbon canister evaporation and evaporation sealed chamber (2) and the pipeline assembly (10). The SV1 solenoid valve allows the gas to circulate between the carbon canister evaporation and evaporation sealed chamber (2) and the carbon canister (1). The pipeline assembly (10) and the SV1 solenoid valve are located within the vehicle evaporation sealed chamber (4). By controlling the opening and closing of the SV2 solenoid valve, the gas can be controlled to circulate between the carbon canister evaporation and evaporation sealed chamber (2) and the pipeline assembly (10) connected to the SV2 solenoid valve. After detecting the hydrocarbon concentration in the carbon canister (1), the SV1 solenoid valve is closed by controlling the SV2 solenoid valve, and the circulation pump (5) is turned on, so that the residual hydrocarbons circulate between the pipeline and the carbon canister evaporation and evaporation sealed chamber (2), thus avoiding the residual gas in the pipeline from affecting the stability of HFID detection in the carbon canister evaporation and evaporation sealed chamber (2).

2. The carbon canister emission recycling sampling device according to claim 1, characterized in that: The carbon canister's escape emission evaporation sealed chamber (2) contains a gas bag (3), and the gas bag (3) is externally connected to a gas supply system, which includes: Pressure reducing valve, mass flow valve FV1, V1 solenoid valve, V3 solenoid valve and positive and negative pressure sensors (9); One end of the pressure reducing valve is connected to a gas source, and one end of the V3 solenoid valve is connected to the atmospheric balance port of the gas bag. The pressure reducing valve and the V3 solenoid valve are connected to the gas bag (3) through a gas single passage. The mass flow valve FV1, the V1 solenoid valve and the positive and negative pressure sensor (9) are installed in sequence on the gas single passage. Among them, the positive and negative pressure sensor (9) and the V3 solenoid valve are also connected to the V2 solenoid valve. The mass flow valve FV2 is installed at the V2 solenoid valve.

3. The carbon canister emission recycling sampling device according to claim 2, characterized in that: The air bag (3) is equipped with a butterfly breathing valve. The butterfly breathing valve is connected to the external air pressure through the atmospheric balance port of the air bag. The air bag (3) interacts with the external gas through the butterfly breathing valve, thereby maintaining the air pressure balance of the carbon canister evaporation and evaporation sealed chamber (2).

4. A carbon canister emission circulation sampling method, employing the carbon canister emission circulation sampling equipment as described in any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Connect the carbon canister (1) to the carbon canister evaporation and evaporation sealed chamber (2). By changing the ambient temperature inside the carbon canister evaporation and evaporation sealed chamber (2), simulate the day and night changes in the ambient temperature around the car when it is parked. Step 2: Evacuate the gas bag (3) in the carbon canister evacuation and discharge evaporation sealed chamber (2), and then inflate the gas bag (3) to make the volume inside the chamber reach the specified volume; Step 3: During the process of evacuating and filling the air bag (3) to maintain the balance inside the chamber, open the balance valve inside the chamber, close the carbon canister evaporation evaporation sealed chamber (2), and perform initial sampling inside the carbon canister evaporation evaporation sealed chamber (2), record the data, and at the same time open the SV2 solenoid valve. Then, conduct the evaporation experiment of the carbon canister (1), and set an appropriate detection time of 24h-72h according to customer needs. Step 4: 1 minute before the carbon canister (1) emission test reaches 24h-72h, close the SV2 solenoid valve, open the SV1 solenoid valve and start the circulation pump (5) to make the hydrocarbon waste gas circulate between the pipeline and the carbon canister emission evaporation sealed chamber (2) for 1min-10min before final sampling.

5. The carbon canister emission recycling sampling method according to claim 4, characterized in that: The carbon canister is equipped with a V4 solenoid valve for maintaining the balance inside the chamber, and a V5 sampling valve and a V6 return sampling valve for controlling the inlet and outlet of the HFID calibration gas, respectively. The carbon canister evaporation and evaporation sealed chamber (2) is also equipped with a temperature sensor (8) and a differential pressure sensor (7), and a fan (6) is installed inside the carbon canister evaporation and evaporation sealed chamber (2). The carbon canister evaporation and evaporation sealed chamber (2) is also equipped with a propane injection port and a pipeline assembly connection port.

6. The carbon canister emission recycling sampling method according to claim 4, characterized in that: Step two, evacuating the air bag (3), includes the following steps: S1: Solenoid valves V1 and V3 are closed, with a delay of 10 seconds; S2: Open V4 solenoid valve, delay for 2 seconds; S3: Open the V2 solenoid valve and the FV circulation pump (5), and make a judgment; Within 10 minutes after the V2 solenoid valve is opened, the differential pressure sensor (7) is less than or equal to -3kp. After the V2 solenoid valve is closed, there is a 2-second delay, and then the V4 solenoid valve is closed. If the differential pressure sensor (7) detects that the pressure in the carbon canister evaporation evaporation sealed chamber (2) is greater than -3kp within 10 minutes after the V2 solenoid valve is opened, it will alarm and stop the machine, and automatically close the V2 solenoid valve. Then, after a 2-second delay, the V4 solenoid valve will be closed.

7. A carbon can vent emission cycle sampling method according to claim 4 wherein: Step two, inflating the air bag (3), includes the following steps: A1: Confirm that solenoid valve V2 is in the closed position; A2: Confirm that V3 is in the off state; A3: Open solenoid valve V1; A4: After a 2s delay, open the mass flow valve FV1, inject gas into the gas bag (3), and then make a judgment. A5: After inflation is complete, close the mass flow valve FV1 and then close the solenoid valve V1 after a 2-second delay.

8. A carbon can vent emission cycle sampling method according to claim 4, wherein: Step three, sampling inside the cabin, includes the following steps: V1: Check whether the storage volume of zero gas, hydrogen-nitrogen mixture, and standard gas is sufficient; V2: HFID power on; V3: Enter the standard gas concentration and confirm the sampling range; V4: HFID automatic calibration; V5: Carbon canister escapes from the evaporation sealed chamber (2) Sampling: Close V4 and sample balance valve, and open V5 sampling valve and V6 return sampling valve at the same time; V6: Sample for 2 minutes, take the value 0.1 seconds before the end, and sample once per hour; V7: Standby.

9. The carbon canister emission recycling sampling method according to claim 4, characterized in that: Step one simulates changes in the ambient temperature. Includes the following steps: Q1: Confirm that solenoid valves V3 and V4 are in the closed state; Q2: Turn on the fan (6); Q3: The temperature inside the carbon canister evaporation and sealing chamber (2) is raised to 10℃-70℃; Q4: The air bag (3) is evacuated and the process is completed; then the air bag (3) is inflated and the process is completed, and HFID is automatically calibrated; Q5: Open the air vent valve of the V3 solenoid valve air bag (3); Q6: After a 2-second delay, the test timing will begin; Q7: Initial sampling, record sampling data, including sampling time, sampling temperature, sampling absolute pressure, sampling concentration (ppmc1), sampling mass concentration, and mass concentration difference; Q8: Set HFID to automatically calibrate 6 minutes before the hour arrives; Q9: Set the final sampling to be performed 2 minutes before the hour arrives, sample for 2 minutes and record the data; Q10: True or False; Q11: The V3 solenoid valve is closed, and the test is over.

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