Carbon tank pressure drop detection method and system

Abstract

The invention discloses a carbon tank pressure drop detection method and system. The method comprises the steps that a gas source is provided for supplying gas to a to-be-detected port of a carbon tank and controlling the flow; processing other ports to establish a test flow path; after the test flow path is established, pressure measurement values are collected for multiple times at a first frequency within a first preset duration, and a first average pressure value P1'is obtained through calculation; in the first reference state, pressure reference values are collected multiple times at a second frequency within a second preset duration, and a second average pressure value P0'is obtained through calculation; a voltage drop detection value [Delta] P'is determined based on a difference between P1 'and P0'. The invention also discloses a system for realizing the method, which generally comprises a gas source supply unit, a flow control unit, a port processing unit, a pressure sensing unit and a control processing unit configured to execute the calculation and control logic, and can be integrated on a multi-station turntable. The test pressure and the reference pressure are sampled for multiple times and averaged, so that the influence of fluctuation and drift is effectively inhibited, and the stability and the accuracy of pressure drop detection of the carbon tank are remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon canister detection, and in particular relates to a carbon canister pressure drop detection method and system. Background Art

[0002] The carbon canister is a key component in modern vehicles' fuel evaporation control systems. It absorbs gasoline vapor from the fuel tank and, when the engine is running, releases the absorbed gasoline vapor into the engine's intake manifold for combustion, reducing atmospheric pollution. The performance of the carbon canister directly impacts a vehicle's emissions and fuel economy.

[0003] As an important gas storage container, the desorption and adsorption process of the gas inside the carbon canister reflects the product's sealing and gas transmission performance. Traditional detection methods mainly use flow meters and differential pressure gauges to read the air pressure value of the product interface, and directly calculate the pressure drop based on the pressure measurement values ​​at two moments. However, due to certain instrument fluctuations in the flow meter and pressure gauge themselves, especially the baseline value read after the equipment is initialized, it is easy to drift due to the influence of air pressure, flow and environment, resulting in a large error in the differential calculation between the subsequent measurement value and the baseline value; at the same time, when the fluctuation limit of the pressure value is encountered during the reading process, the detected pressure drop value may be too large or too small, resulting in poor detection stability and repeatability; in addition, the traditional method lacks strict control over the acquisition time and sampling frequency, and cannot effectively eliminate instantaneous fluctuations, so that the detection error can usually reach or exceed 10%. Therefore, it is urgent to develop a detection method and device that can stably control the initial baseline value and accurately acquire the steady-state pressure value to achieve high-precision monitoring of carbon canister product performance. Summary of the Invention

[0004] The purpose of the present invention is to provide a carbon canister pressure drop detection method and system to solve the technical problems of unstable detection values ​​and low accuracy in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides a method for detecting a carbon canister pressure drop, comprising the following steps:

[0007] Provide a gas source to supply gas to the port to be tested of the carbon canister;

[0008] Controlling the flow rate of the gas source to the port to be tested, while simultaneously opening the atmospheric port of the carbon canister and blocking the other port of the carbon canister to establish a preset test flow path;

[0009] After establishing the preset test flow path, collecting pressure measurement values ​​of a pressure sensor connected to the test flow path multiple times at a first preset frequency within a first preset time period;

[0010] Calculating a first average pressure value based on the multiple collected pressure measurement values;

[0011] In a first reference state, a pressure reference value of the pressure sensor is collected multiple times at a second preset frequency within a second preset time period;

[0012] Calculating a second average pressure value based on the pressure reference values ​​collected multiple times;

[0013] A pressure drop detection value of the carbon canister is determined based on a difference between the first average pressure value and the second average pressure value.

[0014] In some optional embodiments of the present invention, after establishing the preset test flow path, the step further includes waiting for a third preset time period before starting the multiple acquisitions of pressure measurement values; the third preset time period is greater than or equal to 5 seconds.

[0015] In some optional embodiments of the present invention, the first preset duration is greater than or equal to 5 seconds.

[0016] Preferably, the time interval corresponding to the first preset frequency is 0.3 seconds.

[0017] In some optional embodiments of the present invention, the first average pressure value is obtained by summing all pressure measurement values ​​collected within the first preset time period and dividing the sum by the number of collection times.

[0018] In some optional embodiments of the present invention, the first reference state is a state after the test device is reset and the sealing process on the carbon canister port is completely released.

[0019] In some optional embodiments of the present invention, the second preset time length is 5 seconds.

[0020] Preferably, the time interval corresponding to the second preset frequency is 0.2 seconds.

[0021] In some optional embodiments of the present invention, the second average pressure value is obtained by summing all pressure reference values ​​collected within the second preset time period and dividing the sum by the number of collection times.

[0022] In some optional embodiments of the present invention, the pressure of the gas source is 0.3±0.05 MPa.

[0023] In some optional embodiments of the present invention, the air flow rate is 2000 L / H to 8000 L / H.

[0024] In some optional embodiments of the present invention, the method is applied to a rotary test bench having at least two test stations, and the at least two test stations are used to perform desorption pressure drop detection and adsorption pressure drop detection, respectively.

[0025] In a second aspect, the present invention provides a detection system for detecting tank pressure drop using the method described in the first aspect, the detection system comprising:

[0026] A gas supply unit, used for providing test gas;

[0027] a flow control unit, connected to the gas source supply unit, and used to control the gas flow to the test port of the carbon canister;

[0028] A port processing unit, configured to perform corresponding sealing or opening processing on ports other than the port to be tested of the carbon canister, so as to establish a preset test flow path;

[0029] a pressure sensing unit connected to the test flow path and configured to measure the pressure within the flow path;

[0030] A control processing unit, connected to the flow control unit, the port processing unit and the pressure sensing unit;

[0031] Wherein, the control processing unit is configured to:

[0032] Controlling the port processing unit to establish the preset test flow path;

[0033] After establishing the preset test flow path, instructing the pressure sensing unit to collect pressure measurement values ​​multiple times at a first preset frequency within a first preset time period;

[0034] Calculating a first average pressure value based on the multiple collected pressure measurement values;

[0035] In the first reference state, instructing the pressure sensing unit to collect pressure reference values ​​multiple times at a second preset frequency within a second preset time period;

[0036] Calculating a second average pressure value based on the pressure reference values ​​collected multiple times;

[0037] A pressure drop detection value of the carbon canister is determined based on a difference between the first average pressure value and the second average pressure value.

[0038] In some optional embodiments of the present invention, the detection system further includes a multi-station turntable, and the flow control unit, the port processing unit, and the pressure sensing unit are distributed on at least one testing station of the multi-station turntable.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. Improved detection stability: By sampling both the test pressure and the reference pressure multiple times and taking the average, random fluctuations and noise interference from a single measurement are effectively suppressed, making the calculated pressure drop value more stable and less prone to fluctuations. The improved deviation can be controlled within 5%, significantly improving stability.

[0041] 2. Improved Detection Accuracy: The reference pressure uses a dynamic average measurement method to better track slow changes or drifts in the system baseline state, avoiding the systematic errors caused by using a fixed reference pressure value. As a result, the absolute accuracy of the carbon canister pressure drop detection value calculated based on the more accurate first and second average pressure values ​​is also improved. The improved product test values ​​are very stable, generally within a range of ±0.02 kPa.

[0042] 3. Reduced misjudgment rate: As the stability and accuracy of the test results are improved, the pressure drop value ΔP' can more truly reflect the performance of the carbon canister itself, reducing misjudgment caused by the uncertainty introduced by the measurement method itself and improving the reliability of product quality control.

[0043] 4. Easy to implement and integrate: The method of the present invention mainly improves the data acquisition and processing methods. It can be implemented on existing automated testing equipment (especially equipment with PLC or industrial computer) through software programming. The hardware changes are small or no changes are required, and it is easy to promote and apply on existing production lines.

[0044] The present invention effectively suppresses the influence of fluctuation and drift by sampling the test pressure and the reference pressure multiple times and taking the average, and dynamically obtains the reference value, which significantly improves the stability and accuracy of pressure drop detection and reduces the misjudgment rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments disclosed in the present invention, the drawings of the embodiments will be briefly introduced below. These drawings are only used for illustrative purposes and are not intended to limit the scope of protection of the present invention.

[0046] Figure 1 A schematic flow chart of a carbon canister pressure drop detection method according to an embodiment of the present invention;

[0047] Figure 2 is a structural block diagram of a carbon canister pressure drop detection system according to an embodiment of the present invention;

[0048] Figure 3 Schematic diagram of a four-station turntable detection system in an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The technical solutions of the present invention (including preferred technical solutions) are further described in detail below by way of accompanying drawings and listing some optional embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0050] The terms "first", "second", etc. in the embodiments of the present invention are used only to distinguish descriptions and do not imply any order or importance. The terms "comprises", "includes", or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, article, or device that includes the element.

[0051] Example 1

[0052] This embodiment provides a carbon canister pressure drop detection method, which includes the following steps:

[0053] First, a gas source is provided to supply gas to the port to be tested (eg, the desorption port or the adsorption port) of the carbon canister. Generally, the pressure of the gas source is 0.3±0.05 MPa.

[0054] Then, a flow control unit (such as a flow controller) is used to precisely control the gas flow to the port to be tested so that it reaches a preset test flow value. Generally, the gas flow rate is 2000L / H to 8000L / H.

[0055] At the same time, according to the test type (desorption or adsorption), other ports except the port to be tested are processed accordingly, that is, one of the ports is blocked and the atmospheric port is opened, thereby establishing a preset flow path that meets the test requirements.

[0056] After the flow path is established and stabilized, within a preset measurement time period (first preset time period T1), the current pressure measurement value is continuously or intermittently collected multiple times at a specific sampling frequency (first preset frequency) using a pressure sensing unit (such as a pressure gauge or pressure sensor) connected to the test flow path.

[0057] Then, all or the filtered pressure measurement values ​​collected within the first preset time period are processed to calculate a first average pressure value P1' that can represent the average pressure level within the period. Preferably, the calculation method is to calculate the arithmetic mean of all collected values.

[0058] In addition, the method also requires determining a reference pressure value. Unlike the prior art approach of using a fixed initialization value, the method of the present invention is to acquire the pressure reference value of the pressure sensor multiple times at a specific reference sampling frequency (a second preset frequency) within another preset reference time period (a second preset time period) after the test device is reset, the port seal is fully released, and the pipeline is at a state close to atmospheric pressure or a certain stable reference pressure.

[0059] Then, all or the filtered pressure reference values ​​collected within the second preset time period are processed to calculate a second average pressure value P0' that can represent the average pressure level under the reference state. Preferably, the calculation method is also to calculate the arithmetic mean of all collected values.

[0060] Finally, the final carbon canister pressure drop detection value ΔP′ is obtained by calculating the difference between the first average pressure value P1 ′ and the second average pressure value P0 ′, where ΔP′= P1 ′− P0 ′.

[0061] By taking multiple samples and calculating the average to determine P1' and P0', the potential transient fluctuations and noise present in a single measurement can be effectively smoothed out, making the P1' and P0' values ​​more stable and representative. In particular, the P0' determination no longer relies on a fixed initial value that may have drifted. Instead, it is dynamically derived based on the average reference pressure obtained from multiple actual measurements, better reflecting the current system baseline state. Consequently, the pressure drop value ΔP' calculated based on this P1' and P0' calculations will exhibit significantly improved stability and accuracy compared to existing technologies.

[0062] In some embodiments of the present invention, in order to simulate the state of the carbon canister desorbing from the engine, the port to be tested is the desorption port of the carbon canister. At this time, the adsorption port of the carbon canister is blocked and its atmospheric port is open.

[0063] In order to simulate the state of fresh air entering the carbon canister or fuel vapor entering the carbon canister, the port to be tested is the adsorption port of the carbon canister. At this time, the desorption port of the carbon canister is blocked and its atmospheric port is opened.

[0064] In some embodiments of the present invention, after establishing a preset test flow path, particularly after performing operations such as port blocking, a waiting time (third preset duration T) can be set, for example, T ≥ 5 seconds, to allow the flow and pressure in the flow path to reach a relatively stable state before collecting pressure measurements for calculating P1'. This helps ensure that the collected P1' data better reflects the pressure under steady-state conditions.

[0065] In some embodiments of the present invention, the measurement duration (first preset duration T1) for collecting P1' data can be set to ≥5 seconds to ensure that a sufficient number of sample points are collected and to improve the statistical significance and stability of the average value.

[0066] In some embodiments of the present invention, the sampling frequency (first preset frequency) for collecting P1' data can be set to a corresponding time interval of 0.3 seconds. This is an empirical value that can ensure the sampling density while avoiding the additional noise or processing burden that may be introduced by too high a frequency.

[0067] In some embodiments of the present invention, P1' is calculated by accumulating and summing all m pressure measurement values ​​Pm collected at a first preset frequency within a first preset time period T1, and then dividing by the number of collections m, that is, P1'=ΣPm / m.

[0068] In some embodiments of the present invention, the reference state (first reference state) for collecting P0' data is defined as: the test equipment completes the reset operation, and the port processing unit used for testing (such as the blocking cylinder) is completely released or opened, so that the test pipeline is connected to the atmosphere or is in a known, stable non-test pressure state. Selecting this state to collect P0' can better reflect the baseline pressure level of the system under non-test load. The reference duration (second preset duration) for collecting P0' data can be set to 5 seconds.

[0069] In some embodiments of the present invention, the sampling frequency (second preset frequency) for collecting P0' data can be set to a corresponding time interval of 0.2 seconds. This is shorter than the sampling interval of P1'. This may be because the pressure change under the reference state may be smaller. Increasing the sampling rate helps to capture the reference value more accurately.

[0070] In some embodiments of the present invention, P0' is calculated by accumulating and summing all n pressure reference values ​​Pn collected at a second preset frequency within a second preset time period, and then dividing by the number of collection times n, ie, P0'=ΣPn / n.

[0071] In some embodiments of the present invention, the method of the present invention can be effectively applied to automated testing systems, especially those using multi-station turntables, e.g. Figure 3 The system shown has a four-station turntable. Desorption testing (such as station S2) and adsorption testing (such as station S3) can be set up at different stations. Once the turntable is rotated into position, the pressure drop test method described above can be performed in parallel or serially at each station. For example, station S1 loads material, station S2 performs a desorption test, station S3 performs an adsorption test, station S4 unloads material, and then the turntable rotates to enter the next cycle.

[0072] Example 2

[0073] This embodiment describes an automated carbon canister pressure drop detection system using a 4-station turntable. The system applies the detection method of the present invention and can perform desorption pressure drop and adsorption pressure drop detection of the carbon canister simultaneously or sequentially.

[0074] like Figure 2 As shown, the system includes a gas supply unit 101, a flow control unit 102 (selecting an appropriate range based on the test type), a port processing unit 103 (including a connector for connecting the test port and a mechanism for blocking the non-test port), a pressure sensing unit 104, and a control processing unit 107. Assuming the test bench is used for desorption testing, the flow controller 102 is connected to the canister desorption port pipeline, the port processing unit 103 is responsible for blocking the adsorption port and ensuring that the atmospheric port is open, and the pressure sensor 104 measures the desorption port pressure.

[0075] The gas supply unit 101 is used to provide a test gas with stable pressure, cleanness and dryness. In some embodiments of the present invention, the pressure of the gas source is 0.3±0.05 MPa, and the flow rate is 2000L / H to 8000L / H.

[0076] The flow control unit 102 is connected to the gas supply unit 101 and is used to accurately control the gas flow output to the test port of the carbon canister.

[0077] The port processing unit 103 is used to automatically block or open the non-test ports of the carbon canister according to the test requirements to establish a test flow path.

[0078] The pressure sensing unit 104 is installed on the pipeline connected to the port to be measured, and is used to measure the pressure in the flow path in real time.

[0079] The control processing unit 107 can be a PLC or industrial computer, connected to the above units via a bus or hard wiring; it is responsible for the operation control, data processing and human-computer interaction of the entire system (it can be connected to an HMI touch screen (not shown)). It is used to:

[0080] Control the flow control unit 102 to set and maintain the test flow;

[0081] Control the port processing unit 103 to perform port blocking / opening actions;

[0082] According to the preset parameters (first duration T1, first frequency), trigger and receive multiple pressure measurement values ​​of the pressure sensing unit 104 in the test state;

[0083] Calculating a first average pressure value P1 ′ based on these measured values;

[0084] Identifying or controlling the system to enter a first reference state;

[0085] According to the preset parameters (second duration, second frequency), trigger and receive multiple pressure reference values ​​of the pressure sensing unit 104 in the reference state;

[0086] Calculate a second average pressure value P0' based on these reference values;

[0087] Finally, the difference between P1' and P0' is calculated to obtain the pressure drop detection value ΔP', and the result can be output for display, storage, or used to determine whether the product is qualified or not.

[0088] like Figure 3 As shown, the system is centered on a rotatable turntable with four workstations evenly distributed on it: S1 (manual loading), S2 (desorption detection), S3 (adsorption detection) and S4 (product unloading).

[0089] The S2 and S3 test stations are respectively equipped with device modules for performing voltage drop tests.

[0090] Station S2 (desorption detection): Equipped with a first flow control unit 102a, a first pressure sensing unit 104a, and a first port processing unit 103a. The first flow control unit 102a (e.g., a flow controller) is used to precisely control the air flow to the carbon canister desorption port. The first pressure sensing unit 104a is installed in the pipeline connecting to the desorption port to measure the pressure at that point. The first port processing unit 103a includes a sealing head A for automatically sealing the carbon canister adsorption port and a mechanism to ensure that the atmospheric port is open (or in the default state).

[0091] Station S3 (Adsorption Detection): Equipped with a second flow control unit 102b, a second pressure sensing unit 104b, and a second port processing unit 103b. The second flow control unit 102b (e.g., a flow controller) is used to precisely control the air flow to the carbon canister adsorption port. The second pressure sensing unit 104b is installed in the pipeline connecting to the adsorption port to measure the pressure at that point. The second port processing unit 103b includes a sealing head B for automatically sealing the carbon canister desorption port and a mechanism to ensure that the atmospheric port is open (or in the default state).

[0092] The control processing unit 107 is connected to and controls the rotary drive mechanism (not shown) of the turntable, the flow controllers (102a, 102b) of the S2 and S3 stations, and the actuators (such as cylinders, solenoid valves) in the port processing units (103a, 103b) through signal lines or buses, and receives pressure signals from pressure sensors (104a, 104b).

[0093] A complete test cycle of the present invention is described below:

[0094] Step S01: loading and positioning.

[0095] At station S1, the operator places the canister to be tested on the fixture of the turntable. The turntable rotates, moving the fixture with the new canister from S1 to station S2. Simultaneously, the canister that completed the S3 test in the previous cycle may be moved to station S4, the canister that completed the S2 test may be moved to station S3, and the empty S4 station may be moved to station S1 to await loading. Once the turntable is in place, the fixture may undergo precise positioning.

[0096] Step S02: Establish a test flow path (taking S2 desorption test as an example).

[0097] When the carbon canister arrives at the S2 station, the control processing unit 107 instructs the first port processing unit 103a of the S2 station to act: connect the test gas circuit (including the flow controller 102a and the pressure sensor 104a) to the desorption port of the carbon canister, and at the same time, drive the sealing head A to reliably block the adsorption port of the carbon canister. The atmospheric port of the carbon canister remains naturally open. At this point, the preset flow path for the desorption test of the S2 station is established. Similarly, at the S3 station, the second port processing unit 103b will connect the adsorption port, block the desorption port, and open the atmospheric port.

[0098] Step S03: Stabilize and wait.

[0099] After the port processing is complete, the control processing unit 107 activates the first flow controller 102a, causing it to output the preset desorption test flow rate. To allow the airflow and pressure within the pipeline to reach a stable state, the system waits for a preset stabilization time, T, which can be set to 5 seconds or longer. A similar operation is performed at station S3, activating the second flow controller 102b to output the adsorption test flow rate and waiting for the same or a different stabilization time.

[0100] Step S04: Collect P1 measurement value (calculate P1').

[0101] After the waiting time T ends, the control processing unit 107 starts to collect the readings of the first pressure sensing unit 104a at the S2 station. The collection process lasts for a first preset time duration T1 (for example, T1 = 5 seconds). During the T1 period, multiple samples are taken at a first preset frequency (for example, once every 0.3 seconds). Assume that m = 17 pressure values ​​P are collected in 5 seconds. S2，1 , P S2，2 ,...,P S2，17 The control processing unit 107 stores these values. Simultaneously (or serially), similar operations are performed at the S3 station to collect m' pressure values ​​P of the second pressure sensing unit 104b under adsorption test conditions. S3，1 , P S3，2 ,...,P S3，m' .

[0102] Step S05: Calculate a first average pressure value P1'.

[0103] After the acquisition is completed, the control processing unit 107 calculates P1' of the S2 station: P1' S2 =(P S2，1 +P S2，2 +...+P S2，17 ) / 17. Similarly, calculate P1' of S3 station: P1'S3=(P S3，1 +P S3，2 +...+P S3，m' ) / m'.

[0104] Step S06: Entering the reference state and collecting the P0 reference value (calculating P0').

[0105] The acquisition of P0' can be performed at a specific stage of each test cycle, or when the device is started, reset, or at a specific calibration cycle. Here is a way to integrate P0' acquisition into the test process, for example, it can be performed after the test is completed and the port processing unit is released. Or, more commonly, P0' is used as a relatively stable but regularly updated reference value when the device is idle and reset. Assume that after the most recent reset of the device is completed, the control processing unit 107 confirms that all port processing units (sealing heads A and B) are in a fully released state, and the test pipeline is connected to the atmosphere or is at a stable reference pressure. At this time, the control unit instructs the pressure sensor 104a of S2 and the pressure sensor 104b of S3 to perform multiple sampling at a second preset frequency (for example, once every 0.2 seconds) within a second preset time length (for example, 5 seconds). Assume that n = 25 reference pressure values ​​P0 are collected. S2，1 ,...,P0 S2，25 and P0 S3，1 ,...,P0 S3， 25.

[0106] Step S507: Calculate the second average pressure value P0'.

[0107] The control processing unit 107 calculates P0': P0' S2 =(P0 S2，1 +...+P0 S2，25 ) / 25;P0' S3 =(P0 S3，1 +...+P0 S3，25 ) / 25. These two P0' values ​​can be stored and used as reference values ​​in a certain number of subsequent test cycles, or they can be remeasured and updated in each cycle, depending on the real-time requirements and the stability of the system state.

[0108] In some embodiments of the present invention, the first reference value P0 is the value after the device is initialized, and the new reference value P0' is the average value collected after reset and release. In this way, a more accurate benchmark that is more suitable for the current device state can be obtained.

[0109] Step S08: Calculate the pressure drop value ΔP'.

[0110] The control processing unit 107 uses the P1' calculated by the current test cycle S2 and the stored (or just calculated) P0' S2 , calculate the desorption pressure drop: ΔP' S2 =P1' S2 -P0' S2 Similarly, calculate the adsorption pressure drop: ΔP' S3 =P1' S3 -P0' S3 .

[0111] Step S509: Result determination and material cutting.

[0112] Calculated ΔP' S2 and ΔP' S3 The test result is compared with the preset acceptable range to determine whether the canister is qualified. When the turntable rotates and brings the tested canister to the S4 station, a feeding mechanism (such as a robot or slide) removes the canister or causes it to slide into a collection area. Qualified and unqualified products may be processed separately.

[0113] Step S510: Loop.

[0114] The turntable continues to rotate and the next test cycle begins.

[0115] A set of test data in the prior art is shown in Table 1, and a set of test data using the present invention is shown in Table 2:

[0116] Table 1

[0117]

[0118] In Table 1, for ST2, the maximum value is 0.81, the minimum value is 0.76, the average value is 0.78, and the deviation is (0.81-0.76) / 0.78=6.4%. For ST3, the maximum value is 1.14, the minimum value is 1.06, the average value is 1.08, and the deviation is (1.14-1.06) / 1.08=7.4%.

[0119] Table 2

[0120]

[0121] In Table 2: for ST2, (0.46-0.44) / 0.45=4.5%; for ST3, (1.01-0.98) / 0.99=4%.

[0122] Compared with the prior art, the timing and method of value taking in the present invention have been improved, which greatly improves the stability. The value of product test is very stable, basically within the range of ±0.02Kpa.

[0123] The present invention improves the method for obtaining the key pressure value P1 and reference pressure value P0 in the carbon canister pressure drop test. Specifically, it adopts a method of multiple sampling under specific conditions and calculating the average value (P1' and P0'), replacing the traditional method of reading a single point P1 value and using a fixed P0 value. This method effectively overcomes the instability caused by measurement signal fluctuations and system reference drift, significantly improves the stability and accuracy of the pressure drop detection results (ΔP' = P1'-P0'), and reduces the risk of misjudgment. The detection method, device, and system provided by the present invention are particularly suitable for carbon canister quality control on automated production lines with high requirements for detection accuracy and stability.

[0124] While the specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to these embodiments. Various modifications are possible within the knowledge of those skilled in the art without departing from the spirit of the present invention. For example, the specific sampling frequency, sampling duration, and waiting time can be adjusted based on actual equipment characteristics and test requirements; the number and layout of the turntable stations can also be varied; and multiple options are available for the acquisition timing and update strategy of P0'. All such equivalent substitutions or modifications are intended to be within the scope of protection of the present invention.

Claims

1. A carbon canister pressure drop detection method, characterized in that: The following steps are involved: Provide a gas source to supply gas to the port to be tested of the carbon canister; Controlling the flow rate of the gas source to the port to be tested, while simultaneously opening the atmospheric port of the carbon canister and blocking the other port of the carbon canister to establish a preset test flow path; After establishing the preset test flow path, collecting pressure measurement values ​​of a pressure sensor connected to the test flow path multiple times at a first preset frequency within a first preset time period; Calculating a first average pressure value based on the multiple collected pressure measurement values; In a first reference state, a pressure reference value of the pressure sensor is collected multiple times at a second preset frequency within a second preset time period; Calculating a second average pressure value based on the pressure reference values ​​collected multiple times; A pressure drop detection value of the carbon canister is determined based on a difference between the first average pressure value and the second average pressure value.

2. The carbon canister pressure drop detection method according to claim 1, characterized in that: After the preset test flow path is established, the method further includes waiting for a third preset time period before starting the multiple acquisitions of pressure measurement values; the third preset time period is greater than or equal to 5 seconds.

3. The carbon canister pressure drop detection method according to claim 1, characterized in that: The first preset duration is greater than or equal to 5 seconds; the time interval corresponding to the first preset frequency is 0.3 seconds.

4. The carbon canister pressure drop detection method according to claim 1, characterized in that: The first average pressure value is obtained by summing all pressure measurement values ​​collected within the first preset time period and dividing the sum by the number of collection times.

5. The carbon canister pressure drop detection method according to claim 1, characterized in that: The first reference state is a state after the test device is reset and the sealing process on the carbon canister port is completely released.

6. The carbon canister pressure drop detection method according to claim 1, characterized in that: The second preset duration is 5 seconds; the time interval corresponding to the second preset frequency is 0.2 seconds.

7. The carbon canister pressure drop detection method according to claim 1, characterized in that: The second average pressure value is obtained by summing all pressure reference values ​​collected within the second preset time period and dividing the sum by the number of collection times.

8. The carbon canister pressure drop detection method according to claim 1, characterized in that: The pressure of the gas source is 0.3±0.05 MPa; the air flow rate is 2000 L / H to 8000 L / H.

9. A detection system for detecting tank pressure drop using the detection method according to any one of claims 1 to 8, characterized in that: The detection system comprises: A gas supply unit, used for providing test gas; a flow control unit, connected to the gas source supply unit, and used to control the gas flow to the test port of the carbon canister; A port processing unit, configured to perform corresponding sealing or opening processing on ports other than the port to be tested of the carbon canister, so as to establish a preset test flow path; a pressure sensing unit connected to the test flow path and configured to measure the pressure within the flow path; A control processing unit, connected to the flow control unit, the port processing unit and the pressure sensing unit; Wherein, the control processing unit is configured to: Controlling the port processing unit to establish the preset test flow path; After establishing the preset test flow path, instructing the pressure sensing unit to collect pressure measurement values ​​multiple times at a first preset frequency within a first preset time period; Calculating a first average pressure value based on the multiple collected pressure measurement values; In the first reference state, instructing the pressure sensing unit to collect pressure reference values ​​multiple times at a second preset frequency within a second preset time period; Calculating a second average pressure value based on the pressure reference values ​​collected multiple times; A pressure drop detection value of the carbon canister is determined based on a difference between the first average pressure value and the second average pressure value.

10. The detection system according to claim 9, characterized in that: The detection system further includes a multi-station turntable, and the flow control unit, the port processing unit, and the pressure sensing unit are distributed on at least one testing station of the multi-station turntable.

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