Carbon tank escape emission evaporation closed chamber circulation sampling equipment and sampling method

Abstract

The invention discloses carbon tank escape emission evaporation closed chamber circulation sampling equipment and a sampling method, and relates to the technical field of motor vehicle emission source test equipment. Comprising a carbon tank escaping, discharging and evaporating closed chamber, a pipeline assembly and a circulating pump, an SV1 electromagnetic valve and an SV2 electromagnetic valve are arranged between the carbon tank escaping, discharging and evaporating closed chamber and a carbon tank, and the circulating pump is arranged between the SV1 electromagnetic valve and the carbon tank escaping, discharging and evaporating closed chamber. The circulation of hydrocarbon between the carbon tank and the carbon tank escape discharge evaporation closed chamber can be controlled by controlling the SV1 solenoid valve, the concentration of the hydrocarbon is detected, and the circulation of residual hydrocarbon between the pipeline and the carbon tank escape discharge evaporation closed chamber can be controlled by controlling the SV2 solenoid valve and closing the SV1 solenoid valve. The residual gas in the pipeline is prevented from influencing the detection stability of the carbon tank escaping and discharging evaporation closed chamber, so that the detected numerical value is stable, and the test accuracy is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of motor vehicle emission source testing equipment, and specifically relates to a carbon canister escape emission evaporation closed chamber circulation sampling device and a sampling method. Background Technique

[0002] Currently, an evaporation emission closed chamber is commonly used to detect the hydrocarbon emissions of vehicles. The closed chamber can simulate various environmental conditions during the actual use of the vehicle, such as different temperatures, humidities, and air pressures, etc. This can more accurately detect the hydrocarbon emissions of the vehicle during actual operation and avoid interference from external factors during detection in an open environment.

[0003] The evaporation closed chamber for detecting hydrocarbon emissions and its vehicle integrated test chamber with the application number 202322282124.0 disclose a detection method for detecting the hydrocarbon emissions of vehicles using an evaporation closed chamber, which can make the gas distribution in the evaporation emission closed chamber and the vehicle integrated environmental test chamber more uniform.

[0004] However, during the implementation of the above evaporation closed chamber and its vehicle integrated test chamber, there may be residual gas in the gas pipeline during the emission process. Since a part of the gas will remain in the gas pipeline, during the actual detection process, there are certain errors in the detected data. To make the detected values accurate and stable, the present invention provides a new detection device and a sampling method. Summary of the Invention

[0005] The purpose of the present invention is to provide a carbon canister escape emission evaporation closed chamber circulation sampling device and a sampling method to solve the problems raised in the above background technique.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A carbon canister escape emission circulation sampling device, comprising: A carbon canister escape emission evaporation closed chamber, a pipeline assembly, and a circulation pump; An SV1 solenoid valve and an SV2 solenoid valve are arranged between the carbon canister escape emission evaporation closed chamber and the carbon canister. A circulation pump is arranged between the SV1 solenoid valve and the carbon canister escape emission evaporation closed chamber. Among them, the SV2 solenoid valve enables the gas to circulate between the carbon canister escape emission evaporation closed chamber and the pipeline assembly, and the SV1 solenoid valve enables the gas to flow between the carbon canister escape emission evaporation closed chamber and the carbon canister 1. The pipeline assembly 10 and the SV1 solenoid valve are placed in the main evaporation closed chamber.

[0007] Furthermore, regarding this solution, an air bag is arranged inside the carbon canister escape emission evaporation closed chamber, and a gas supply system is externally connected to the air bag. The gas supply system includes: A pressure reducing valve, a mass flow valve FV1, a V1 solenoid valve, a V3 solenoid valve, and a positive and negative pressure sensor; One end of the pressure reducing valve is connected to a gas source. One end of the V3 solenoid valve is connected to the air bag atmospheric balance port. The pressure reducing valve and the V3 solenoid valve are connected to the air bag through a single gas passage. The mass flow valve FV1, the V1 solenoid valve, and the positive and negative pressure sensor are sequentially installed on the single gas passage. Among them, a V2 solenoid valve is also connected between the positive and negative pressure sensor and the V3 solenoid valve, and a mass flow valve FV2 is installed at the V2 solenoid valve.

[0008] Furthermore, regarding this solution, a butterfly breathing valve is arranged inside the air bag. The butterfly breathing valve is communicated with the external air pressure through the air bag atmospheric balance port. The air bag realizes interaction with the external gas through the butterfly breathing valve, thereby maintaining the air pressure balance in the carbon canister escape emission evaporation closed chamber.

[0009] A carbon canister escape emission cyclic sampling method, the above-mentioned carbon canister escape emission cyclic sampling equipment, includes the following steps: Step 1: Connect the carbon canister in the carbon canister escape emission evaporation closed chamber, and simulate the day and night changes of the ambient temperature around the vehicle when parked by changing the ambient temperature in the closed chamber. Step 2: Evacuate the air bag in the carbon canister escape emission evaporation closed chamber, and then inflate the air bag to make the volume in the chamber reach the specified volume. Step 3: Open the chamber balance valve during the process of evacuating and inflating the air bag to maintain the balance in the chamber, close the carbon canister escape emission evaporation closed chamber, and conduct an initial sampling of the carbon canister escape emission evaporation closed chamber, record the data. At the same time, open the SV2 solenoid valve, and then conduct the carbon canister escape emission experiment, and set an appropriate detection time of 24h - 72h according to customer requirements. Step 4: 1 minute before the carbon canister escape emission test reaches 24h - 72h, close the SV2 solenoid valve, open the SV1 solenoid valve and start the air pump to circulate the hydrocarbon waste gas between the pipeline and the carbon canister escape emission evaporation closed chamber for 1min - 10min, and then conduct the final sampling.

[0010] Furthermore, regarding this solution, a V4 solenoid valve for maintaining the balance in the chamber, a V5 sampling valve and a V6 return sample valve for respectively controlling the entry and exit of the HFID calibration gas are installed outside the carbon canister escape emission evaporation closed chamber. A temperature sensor and a differential pressure sensor are also arranged in the carbon canister escape emission evaporation closed chamber, and a fan is arranged inside the carbon canister escape emission evaporation closed chamber. The carbon canister escape emission evaporation closed chamber is also provided with a propane injection port and a sampling pipeline assembly connection port.

[0011] Furthermore, regarding this solution, the evacuation of the air bag in Step 2 includes the following steps: S1: The V1 solenoid valve and the V3 solenoid valve are in the closed state, and a delay of 10s is set. S2: Open the V4 solenoid valve, and set a delay of 2s. S3: Open the V2 solenoid valve and the FV air extraction pump, and make a judgment; Within 10 minutes after the V2 solenoid valve is opened, if the differential pressure sensor is less than or equal to -3 kp, close the V2 solenoid valve and delay for 2S, and then close the V4 solenoid valve; Within 10 minutes after the V2 solenoid valve is opened, if the differential pressure sensor detects that the pressure in the carbon canister escape emission evaporation sealed chamber is greater than -3 kp, alarm and stop the machine, automatically close the V2 solenoid valve, and then delay for 2S to close the V4 solenoid valve.

[0012] Regarding this solution, further, the steps of inflating the air bag in step two include the following steps: A1: Confirm that the V2 solenoid valve is in the closed state; A2: Confirm that V3 is in the closed state; A3: Open the V1 solenoid valve; A4: After a 2s delay, open the mass flow valve FV1, inflate the air bag with gas, and then make a judgment; A5: When the inflation is completed, close the mass flow valve FV1, and after a 2s delay, close the solenoid valve V1.

[0013] Regarding this solution, further, the steps of sampling the cabin in step three include the following steps: V1: Check whether the storage gas volumes of zero gas, hydrogen-nitrogen mixed gas, and calibration gas are sufficient; V2: Power on the HFID; V3: Input the calibration gas concentration and confirm the sampling range; V4: Automatically calibrate the HFID; V5: Sampling in the carbon canister escape emission evaporation sealed chamber: Close V4 and the sample balance valve, and at the same time open the V5 sampling valve and the V6 sample return valve; V6: Sample for 2 minutes, take the value at 0.1S before the end, and the sampling frequency is once per hour; V7: Standby.

[0014] Regarding this solution, further, the steps of simulating the change of the surrounding environment temperature in step one include the following steps: Q1: Confirm that the V3 solenoid valve and the V4 solenoid valve are in the closed state; Q2: Turn on the fan; Q3: Raise the temperature in the carbon canister escape emission evaporation sealed chamber to 10°C - 70°C; Q4: Evacuate the air bag and complete it; then inflate the air bag and complete it, and automatically calibrate the HFID; Q5: Open the air bag ventilation valve of the V3 solenoid valve; Q6: After a 2s delay, the test experiment timing starts; Q7: Initial sampling, record the sampling data, which includes sampling time, sampling temperature, sampling absolute pressure, sampling concentration ppmc1, sampling mass concentration, and mass concentration difference; Q8: Automatically calibrate the HFID 6 minutes before the set hour arrives; Q9: Conduct final sampling 2 minutes before the set hour arrives, sample for 2 minutes and record the data; Q10: Judgment; Q11: Close the V3 solenoid valve, and the test ends.

[0015] Compared with the prior art, the beneficial effects of the present invention are: The carbon canister escape emission evaporation closed chamber circulation sampling device and sampling method can control the flow of hydrocarbons between the carbon canister and the carbon canister escape emission evaporation closed chamber by controlling the SV1 solenoid valve, detect the hydrocarbon concentration, and by controlling the SV2 solenoid valve and closing the SV1 solenoid valve, it can control the flow of residual hydrocarbons between the pipeline and the carbon canister escape emission evaporation closed chamber, avoiding the influence of the residual gas in the pipeline on the stability of the detection in the carbon canister escape emission evaporation closed chamber, making the detected value stable and ensuring the accuracy of the test.

[0016] At the same time, by controlling the volume of the gas bag, the balance in the carbon canister escape emission evaporation closed chamber is maintained. A butterfly breathing valve is provided in the gas bag, and the butterfly breathing valve is connected to the external air pressure through the gas bag atmosphere balance port. The gas bag realizes interaction with the external gas through the butterfly breathing valve, thereby maintaining the air pressure balance in the carbon canister escape emission evaporation closed chamber, making the test results not easily affected by temperature and pressure changes. Description of the Drawings

[0017] Figure 1 It is a schematic flow chart of the carbon canister escape emission evaporation closed chamber circulation sampling method of the present invention; Figure 2 It is a schematic diagram of the carbon canister escape emission evaporation closed chamber circulation sampling device of the present invention; Figure 3 It is a schematic flow chart of the air extraction process in the carbon canister escape emission evaporation closed chamber of the present invention; Figure 4 It is a schematic flow chart of the air filling process in the carbon canister escape emission evaporation closed chamber of the present invention; Figure 5 It is a schematic flow chart of the sampling process of the present invention; Figure 6 It is a schematic flow chart of the day-night alternation test method of the present invention.

[0018] In the figure: 1. Carbon canister; 2. Evaporative emission sealed chamber of the carbon canister; 3. Airbag; 4. Vehicle evaporative sealed chamber; 5. Air pump; 6. Fan; 7. Differential pressure sensor; 8. Temperature sensor; 9. Positive and negative pressure sensor; 10. Pipeline assembly. Detailed implementation mode

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] The following points need to be noted in this embodiment: Zero gas, which is the gas calibrated to zero, can use pure air for zero calibration, and set the reference value as the gas at zero point; HFID automatic calibration refers to that when using a flame ionization detector (HFID), the accuracy and stability of the detector are ensured through an automatic calibration function. HFID automatic calibration usually includes the following steps and precautions: 1. Automatic calibration function: The HFID detector usually has an automatic calibration function, which can be automatically calibrated during the detection process, reducing manual intervention and maintenance costs. This function regularly calibrates the detector through a built-in calibration program to ensure its stable performance.

[0021] 2. Calibration gas: Methane is commonly used as the calibration gas for HFID because methane has a high response in HFID. During the calibration process, by injecting methane gas with a known concentration, 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.

[0022] 3. Calibration period: The calibration period can be set according to the usage frequency and the stability of the detector. Generally speaking, it is recommended to perform automatic calibration once a day or after using for a period of time to ensure that the performance of the detector does not change due to long-term use1.

[0023] 4. Maintenance and troubleshooting: During automatic calibration, attention needs to be paid to the cleanliness and smoothness of the gas path system to ensure the correct flow ratio of hydrogen, carrier gas, and air. Common faults include failure to ignite, excessive base current, high noise, etc. These problems can be solved by checking the gas path system and adjusting the parameters of the detector.

[0024] Through the above steps and methods, the automatic calibration of HFID can be effectively achieved, ensuring its accuracy and stability during use.

[0025] As shown Figure 1 in the figure, the present invention provides a technical solution: a carbon canister purge emission evaporation closed chamber 2 cyclic sampling device, including a carbon canister purge emission evaporation closed chamber 2 and a carbon canister 1. An SV1 solenoid valve and an SV2 solenoid valve are arranged between the carbon canister purge emission evaporation closed chamber 2 and the carbon canister 1. An air pump 5 is arranged between the SV1 solenoid valve and the carbon canister purge emission evaporation closed chamber 2. By controlling the opening and closing of the SV2 solenoid valve, the circulation of gas between the carbon canister purge emission evaporation closed chamber 2 and the pipeline assembly 10 connected to the SV2 solenoid valve can be controlled. The SV1 solenoid valve enables the gas to flow between the carbon canister purge emission evaporation closed chamber 2 and the carbon canister 1. This sampling device is placed inside the vehicle evaporation closed chamber 4.

[0026] By controlling the SV1 solenoid valve, the circulation of hydrocarbons between the carbon canister 1 and the carbon canister purge emission evaporation closed chamber 2 can be controlled to detect the hydrocarbon concentration. By controlling the SV2 solenoid valve, closing the SV1 solenoid valve, and turning on the air pump 5, the remaining hydrocarbons can be made to flow between the pipeline and the carbon canister purge emission evaporation closed chamber 2, avoiding the influence of the residual gas in the pipeline on the stability of the detection in the carbon canister purge emission evaporation closed chamber 2, making the detected value stable, and ensuring the accuracy of the test.

[0027] As shown Figure 2 in the figure, an air bag 3 is installed inside the carbon canister purge emission evaporation closed chamber 2. The air bag 3 is externally connected to a gas supply system, and the gas supply system includes: a pressure reducing valve, a mass flow valve FV1, a V1 solenoid valve, a V3 solenoid valve, and a positive and negative pressure sensor; One end of the pressure reducing valve is connected to a gas source. One end of the V3 solenoid valve is connected to the air bag atmosphere balance port. The pressure reducing valve and the V3 solenoid valve are connected to the air bag 3 through a gas single path. The mass flow valve FV1, the V1 solenoid valve, and the positive and negative pressure sensor are sequentially installed on the gas single path. Among them, a V2 solenoid valve is also connected between the positive and negative pressure sensor and the V3 solenoid valve, and a mass flow valve FV2 is installed at the V2 solenoid valve.

[0028] The carbon canister purge emission evaporation closed chamber 2 of this carbon canister purge emission evaporation closed chamber 2 cyclic sampling device is installed with a V4 solenoid valve for maintaining the balance inside the chamber, as well as a V5 sampling valve and a V6 return sample valve for respectively controlling the inlet and outlet of the HFID calibration gas for gas concentration detection. The carbon canister purge emission evaporation closed chamber 2 is also provided with a positive and negative pressure sensor 9, a differential pressure sensor 7 is arranged inside the carbon canister purge emission evaporation closed chamber 2, and the carbon canister purge emission evaporation closed chamber 2 is also provided with a propane injection port. The ventilation hole of the propane injection port is connected to the sample, and a sample balance valve is arranged at the sample.

[0029] By setting up the airbag 3 to maintain the air pressure balance inside the chamber, one end of the V1 solenoid valve is used to inflate the airbag 3, and one end of the V2 solenoid valve is used to extract air from the airbag 3. By controlling the volume of the airbag 3, the balance inside the carbon canister escape emission evaporation enclosure 2 is maintained. A butterfly breathing valve is installed inside the airbag 3, which is connected to the external air pressure through the airbag atmosphere balance port. The airbag 3 realizes gas interaction with the outside through the butterfly breathing valve, thereby maintaining the air pressure balance in the carbon canister escape emission evaporation enclosure 2, making the test results less susceptible to 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 the tail gas sample gas. During detection, opening the V5 sampling valve allows the hydrocarbon waste gas emitted by the vehicle to enter the sampling pipeline of the detection system. The V6 sample return valve returns the hydrocarbon waste gas after detection to the carbon canister escape emission evaporation enclosure 2 to maintain the pressure balance inside the chamber. The gas concentration inside the chamber is detected through the V5 sampling valve and the V6 sample return valve.

[0030] As Figure 2 shown, for the above-mentioned equipment, we provide a carbon canister escape emission evaporation enclosure circulation sampling method applicable to the above equipment, which specifically includes the following steps: Step 1: Connect the carbon canister 1 to the carbon canister escape emission evaporation enclosure 2, and simulate the day-night change of the ambient temperature around the vehicle when parked by changing the ambient temperature inside the chamber; Step 2: Evacuate the airbag 3 inside the carbon canister escape emission evaporation enclosure 2, and then inflate the airbag 3 to make the volume inside the chamber reach the specified volume; Step 3: Open the chamber balance valve during the process of evacuating and inflating the airbag 3 to maintain the balance inside the chamber, and conduct an initial sampling inside the carbon canister escape emission evaporation enclosure 2, record the data, and then conduct an evaporation emission experiment on the carbon canister 1, with the detection time being 24h - 72h; Step 4: Open the SV2 solenoid valve during the 24h - 72h of testing the carbon canister 1; Step 5: During the 24h - 72h of testing the carbon canister 1, conduct sampling once every hour. When sampling, close the SV2 solenoid valve, open the SV1 solenoid valve and start the air pump 5 to circulate the hydrocarbon waste gas between the pipeline and the carbon canister escape emission evaporation enclosure 2 for 1min - 10min, and then conduct final sampling.

[0031] We confirm the above circulation sampling method through the following experiments: Example 1: Test the influence of the pipeline connected to the carbon canister atmosphere port on the BETP result; Sample requirements: The same fuel system and carbon canister; nylon pipelines with inner diameters of 4mm, 6.5mm, 8mm, and a length of 4m; Test 1

[0032] Test Results

[0033] Analysis: Even when the air flow resistance is very small, there are still large emission differences and the overall emissions are relatively small. It is speculated that the pipeline material adsorbs hydrocarbon waste gas or there is residual hydrocarbon waste gas. Through Test 2, the pipeline material is replaced to detect the influence of the pipeline material on the BETP result.

[0034] Sample Requirements: The same fuel system and carbon canister; PTFE pipelines with inner diameters of 4mm, 6.5mm, 8mm and a length of 4m.

[0035] Test 2

[0036] Test Results

[0037] Analysis: Using PTFE pipelines can slightly reduce the adhesion of hydrocarbon waste gas substances, but the deposition problem still cannot be solved, and there is a large deviation from the actual situation. Consider purging the gas in the pipeline to confirm the influence of the residual gas in the pipeline on the test results.

[0038] Sample Requirements: The same fuel system and carbon canister; PTFE pipelines with inner diameters of 4mm, 6.5mm, 8mm and a length of 4m; Test 3

[0039] Test Results

[0040] Analysis: After purging with air volume and sufficient mixing, the measured value of the carbon canister escape emission is the same as the measured value of "without pipeline". It can be seen that the residual hydrocarbon waste gas substances in the pipeline between Carbon Canister 1 and Carbon Canister Overflow Emission Chamber 2 have a great influence on the detection of Carbon Canister 1.

[0041] Such as Figure 3As shown in the figure, in the second step of the carbon canister purge emission evaporation closed chamber 2 cyclic sampling method, when evacuating the air bag 3, it is necessary to confirm that the V1 solenoid valve and the V3 solenoid valve are in the closed state. Since the V1 solenoid valve and the V3 solenoid valve are closed, the reading of the pressure sensor 9 may be inaccurate during the air extraction process by the air pump 5. To avoid the phenomenon of air retention (when the reading of the pressure sensor is low while the actual pressure is continuously increasing, the air extraction system may continue to work without stopping, which will cause the pressure in the system to gradually increase. After reaching a certain level, the gas cannot be smoothly extracted, forming an air retention phenomenon), it is necessary to open the V4 solenoid valve after a 10s delay, and then open the V2 solenoid valve after a 2s delay and make the following judgment: within 10 minutes after the V2 solenoid valve is opened, if the differential pressure sensor 7 is less than or equal to -3 kPa, close the V2 solenoid valve and then close the V4 solenoid valve after a 2s delay. When the differential pressure sensor 7 detects that the pressure in the carbon canister purge emission evaporation closed chamber is greater than -3 kPa within 10 minutes after the V2 solenoid valve is opened, it alarms and stops the machine, indicating that the evacuation of the air bag 3 is incomplete, automatically closes the V2 solenoid valve, and then closes the V4 solenoid valve after a 2s delay.

[0042] As Figure 4 As shown in the figure, in the second step of the carbon canister purge emission evaporation closed chamber 2 cyclic sampling method, when inflating the air bag 3, it is necessary to confirm that the V2 solenoid valve is in the closed state. After confirming that V3 is also in the closed state, open the V1 solenoid valve, and open the mass flow valve FV1 after a 2s delay. After filling the air bag 3 with gas, make a judgment. When the inflation is completed, close the mass flow valve FV1, and close the solenoid valve V1 after a 2s delay.

[0043] Regarding the evacuation and inflation of the air bag 3, it should be noted that the compressed air source for inflation connection controls the inflation of the air bag 3 through a flow meter, so that the air source pressure is stable and it is convenient to calculate the gas flow through the flow meter. All inflation and evacuation use two independent systems to ensure the stability of the air source pressure.

[0044] In summary, after the carbon canister 1 test is completed, close the SV2 solenoid valve, open the SV1 solenoid valve, and the air pump 5 starts to work, so that the residual gas in the pipeline connecting the carbon canister purge emission evaporation closed chamber and the carbon canister 1 circulates. When detecting the residual gas concentration in the carbon canister purge emission evaporation closed chamber, the detected value is stable, ensuring the accuracy of the test.

[0045] As Figure 5 As shown in the figure, the sampling in the carbon canister purge emission evaporation closed chamber 2 includes the following steps: Step 1: Check whether the storage gas volumes of zero gas, hydrogen-nitrogen mixed gas, and calibration gas are sufficient; Step 2: Power on the HFID; Step 3: Input the calibration gas concentration and confirm the sampling range; Step 4: Automatically calibrate the HFID; Step 5: Sampling in the Evaporative Sealed Chamber 2 for Carbon Canister Purge Emissions. Close the V4 solenoid valve and the sample balancing valve. At the same time, open the V5 sampling valve and the V6 sample return valve. The V5 sampling valve and the V6 sample return valve must be opened simultaneously to ensure that the pressure inside the chamber remains constant during the detection of the gas by the HFID. Step 6: Sample for 2 min and take the value at the last 0.1 s before the end. The sampling frequency is once per hour. Ensure independent sampling for each chamber without interference between chambers. Step 7: Standby.

[0046] As Figure 6 shown, the diurnal variation of the ambient temperature around the vehicle when parked is simulated using the diurnal alternation test method, which includes the following steps: Step 1: Confirm that the V3 solenoid valve and the V4 solenoid valve are in the closed state. Step 2: Turn on the fan 6 to allow the hydrocarbon gas to circulate inside the chamber and reduce the non-uniformity of the hydrocarbon inside the chamber. Step 3: Raise the temperature inside the Evaporative Sealed Chamber 2 for Carbon Canister Purge Emissions to 10°C - 70°C (preset as required). Step 4: Evacuate the gas bag 3 and complete. Step 5: Raise the chamber temperature to 10°C - 70°C (preset temperature), inflate the gas bag 3 and complete. The HFID is automatically calibrated. Step 6: Open the V3 solenoid valve. Step 7: After a 2 s delay, the test timing starts. Step 8: The 0th sampling, sampling the initial state inside the chamber. The sampling data includes sampling time, sampling temperature, sampling absolute pressure, sampling concentration ppmc1, sampling mass concentration, and mass concentration difference. Step 9: Sample once every 1 hour and record the data. Step 10: The HFID is automatically calibrated 6 min before 24H. Step 11: Conduct the 24th sampling 2 min before 24H, sample for 2 min and record the data. Step 12: Judgment. Make judgments on the sampling data in Step 9 respectively. Step 13: Close the V3 solenoid valve and the test ends.

[0047] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood 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 canister purge emission cycle sampling device, characterized in that, Including: A carbon canister purge emission evaporation sealed chamber (2), a pipeline assembly (10), and a circulation pump (5); An SV1 solenoid valve and an SV2 solenoid valve are arranged between the carbon canister purge emission evaporation sealed chamber (2) and the carbon canister (1). A circulation pump (5) is arranged between the SV1 solenoid valve and the carbon canister purge emission evaporation sealed chamber (2). Among them, the SV2 solenoid valve enables gas to circulate between the carbon canister purge emission evaporation sealed chamber (2) and the sampling pipeline assembly. The SV1 solenoid valve enables gas to flow between the carbon canister purge emission evaporation sealed chamber (2) and the carbon canister (1). The sampling pipeline assembly and the SV1 solenoid valve are placed in the main evaporation sealed chamber (4).

2. The carbon canister purge emission cycle sampling device according to claim 1, characterized in that: An airbag (3) is arranged inside the carbon canister purge emission evaporation sealed chamber (2). The airbag (3) is externally connected to a gas supply system. The gas supply system includes: A pressure reducing valve, a mass flow valve FV1, a V1 solenoid valve, a V3 solenoid valve, and a positive and negative pressure sensor (9); One end of the pressure reducing valve is connected to a gas source. One end of the V3 solenoid valve is connected to an airbag atmospheric balance port. The pressure reducing valve and the V3 solenoid valve are connected to the airbag (3) through a single gas path. The mass flow valve FV1, the V1 solenoid valve, and the positive and negative pressure sensor (9) are sequentially installed on the single gas path. Among them, a V2 solenoid valve is also connected between the positive and negative pressure sensor (9) and the V3 solenoid valve. A mass flow valve FV2 is installed at the V2 solenoid valve.

3. The carbon canister purge emission cycle sampling device according to claim 2, wherein: A butterfly breathing valve is arranged inside the airbag (3). The butterfly breathing valve is communicated with the external air pressure through the airbag atmospheric balance port. The airbag (3) realizes interaction with the external gas through the butterfly breathing valve, thereby maintaining the air pressure balance in the carbon canister purge emission evaporation sealed chamber (2).

4. A carbon canister purge emission cycle sampling method, using the carbon canister purge emission cycle sampling device according to any one of claims 1-3, characterized in that, Including the following steps: Step 1: Connect the carbon canister (1) to the carbon canister purge emission evaporation sealed chamber, and simulate the day-night change of the ambient temperature around the vehicle when parked by changing the ambient temperature inside the sealed chamber; Step 2: Evacuate the airbag (3) inside the carbon canister purge emission evaporation sealed chamber (2), and then inflate the airbag (3) to make the volume inside the chamber reach the specified volume; Step 3: Open the chamber balance valve during the process of evacuating and inflating the airbag (3) to maintain the balance inside the chamber, seal the carbon canister purge emission evaporation sealed chamber (2), and conduct an initial sampling inside the carbon canister purge emission evaporation sealed chamber (2), record the data. At the same time, open the SV2 solenoid valve, and then conduct an emission experiment of the carbon canister (1). Set an appropriate detection time of 24h - 72h according to customer requirements; Step 4: 1 minute before the emission test of the carbon canister (1) reaches 24h - 72h, close the SV2 solenoid valve, open the SV1 solenoid valve and start the air pump (5) to circulate the hydrocarbon waste gas between the pipeline and the carbon canister purge emission evaporation sealed chamber (2) for 1 minute - 10 minutes, and then conduct a final sampling.

5. A method for cyclic sampling of a carbon canister purge emission evaporation closed chamber according to claim 4, characterized in that: An external V4 solenoid valve for maintaining the balance inside the chamber, as well as a V5 sampling valve and a V6 return sample valve for respectively controlling the entry and exit of HFID calibration gas, are installed outside the carbon canister purge emission evaporation sealed chamber (2); The carbon canister purge emission evaporation sealed chamber (2) is also provided with a temperature sensor (8) and a differential pressure sensor (7), and a fan (6) is arranged inside the carbon canister purge emission evaporation sealed chamber (2); The carbon canister purge emission evaporation closed chamber (2) is also provided with a propane injection port and a connection port for the sampling pipeline assembly.

6. A method for cyclic sampling of a carbon canister escape emission evaporation closed chamber according to claim 4, characterized in that: The evacuation of the airbag (3) in Step 2 includes the following steps: S1: The V1 solenoid valve and the V3 solenoid valve are in the closed state, with a 10-second delay. S2: Open the V4 solenoid valve, with a 2-second delay. S3: Open the V2 solenoid valve and the FV air pump, and make a judgment. When within 10 minutes after the opening of the V2 solenoid valve, the differential pressure sensor (7) is less than or equal to -3 kPa, close the V2 solenoid valve and delay for 2 seconds, and then close the V4 solenoid valve. When within 10 minutes after the opening of the V2 solenoid valve, the differential pressure sensor (7) detects that the pressure in the carbon canister purge emission evaporation closed chamber is greater than -3 kPa, then alarm and stop the machine, automatically close the V2 solenoid valve, and then close the V4 solenoid valve after a 2-second delay.

7. A method for cyclic sampling of a carbon canister purge emission evaporation closed chamber according to claim 4, characterized in that: The inflation of the airbag (3) in Step 2 includes the following steps: A1: Confirm that the V2 solenoid valve is in the closed state. A2: Confirm that V3 is in the closed state. A3: Open the V1 solenoid valve. A4: After a 2-second delay, open the mass flow valve FV1, and judge after filling the airbag (3) with gas. A5: When the inflation is completed, close the mass flow valve FV1, and close the solenoid valve V1 after a 2-second delay.

8. A method for cyclic sampling of a carbon canister purge emission evaporation closed chamber according to claim 4, characterized in that: The sampling inside the chamber in Step 3 includes the following steps: V1: Check whether the storage gas volumes of zero gas, hydrogen-nitrogen mixed gas, and calibration gas are sufficient. V2: Power on the HFID. V3: Input the calibration gas concentration and confirm the sampling range. V4: Automatically calibrate the HFID. V5: Sampling of the carbon canister purge emission evaporation closed chamber (2): Close V4 and the sample balance valve, and at the same time open the V5 sampling valve and the V6 return sample valve. V6: Sample for 2 minutes, take the value at 0.1 s before the end, and the sampling frequency is once per hour. V7: Standby.

9. A circulating sampling method for a carbon canister purge emission evaporation closed chamber according to claim 4, characterized in that: In Step 1, simulate the change of the ambient temperature, including the following steps: Q1: Confirm that the V3 solenoid valve and the V4 solenoid valve are in the closed state. Q2: Turn on the fan (6). Q3: Raise the temperature inside the carbon canister purge emission evaporation closed chamber (2) to 10°C - 70°C. Q4: Evacuate the airbag (3) and complete it; then inflate the airbag (3) and complete it, and automatically calibrate the HFID. Q5: Open the airbag (3) ventilation valve of the V3 solenoid valve. Q6: After a 2-second delay, start the test timing. Q7: Initial sampling, record the sampling data, and the sampling data includes sampling time, sampling temperature, sampling absolute pressure, sampling concentration ppmc1, sampling mass concentration, and mass concentration difference. Q8: Automatically calibrate the HFID 6 minutes before the set hour arrives. Q9: Conduct final sampling 2 minutes before the set hour arrives, sample for 2 minutes and record the data. Q10: Make a judgment. Q11: Close the V3 solenoid valve, and the test ends.

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