Automobile national six carbon tank air tightness detection device

Abstract

The utility model relates to an automobile national sixth carbon tank air tightness detection device, which comprises an air storage tank, a second adjusting valve, an inflation valve, a flow meter, a pressure sensor, a sensor valve, a temperature sensor, a standard tank, a bypass valve, a main pipeline, a branch pipeline and a plugging exhaust device, the gas storage tank is sequentially connected with a second regulating valve, an inflation valve, a sensor valve and an adsorption opening of the carbon tank through a main pipeline; a branch pipeline connected with the main pipeline in parallel is arranged between the inflation valve and the adsorption port; a standard tank and a bypass valve are mounted on the branch pipeline; the standard tank is connected with the bypass valve through a branch pipeline; a temperature sensor is arranged between the bypass valve and the adsorption port; the temperature sensor is mounted on the main pipeline; a flowmeter and a pressure sensor are arranged between the standard tank and the sensor valve; the flow meter and the pressure sensor are mounted on the main pipeline; and the plugging exhaust device is arranged on the desorption port of the carbon tank. The detection device adopts flow leakage detection, is high in sensitivity and is suitable for low-pressure and micro-leakage detection.

Description

A device for testing the air tightness of carbon canisters in automobiles in accordance with China VI emission standards. Technical Field

[0001] This utility model relates to the field of carbon canister air tightness testing, and in particular to a carbon canister air tightness testing device for automobiles meeting China VI emission standards. Background Technology

[0002] The sealing performance of the fuel system in China VI emission standard vehicles is a crucial characteristic, and these factors collectively determine its key impact on the environment, safety, performance, and regulatory compliance.

[0003] I. Environmental Protection and Emission Control:

[0004] 1. Reduce evaporative emissions:

[0005] The China VI emission standard tightens the limits on hydrocarbon (HC) evaporative emissions by more than 50%. Poor fuel system sealing can cause fuel vapors to escape from the fuel tank, pipelines, or fuel injectors, directly increasing volatile organic compound (VOC) pollution and exacerbating ozone layer depletion and PM2.5 formation.

[0006] 2. Meets OBD monitoring requirements:

[0007] China VI emission standards require on-board diagnostics (OBD) systems to monitor the fuel system's sealing in real time. If a leak with a diameter of ≥1mm is found in the system, the OBD will report a fault code within the corresponding driving cycle.

[0008] II. Legal and regulatory compliance safeguards:

[0009] 1. Type certification testing requirements:

[0010] The China VI Evaporative Emissions Test (SHED) requires vehicles to be parked continuously for 48 hours under day-night temperature variations (22-35℃) with total evaporative emissions <0.7 grams (including degradation coefficient).

[0011] 2. Production Consistency Management:

[0012] Companies are required to conduct random checks on the fuel system airtightness of each batch of vehicles to ensure that the leakage amount complies with regulations.

[0013] As a key component of the fuel system, the sealing performance of the carbon canister assembly is very important. Its airtightness is generally measured by the leakage rate (at a pressure of 14 kPa, the general index is 5 sccm, that is, when the carbon canister is pressurized to a pressure of 14 kPa, the leakage rate is measured to be 5 ml / min).

[0014] Currently, the airtightness testing of carbon canisters often uses pressure drop (pressure drop ΔP = initial pressure P1 - final pressure P2) to calculate the leakage rate. This method, based on the ideal gas equation, has the following problems for carbon canister testing:

[0015] 1. The carbon canister is filled with activated carbon. Activated carbon is a granular substance, and its total volume is affected by the amount filled (the amount cannot be completely consistent due to process limitations), the degree of compaction (fluctuations exist due to the speed of feeding and the intensity of vibration), and the particle size (particle size varies, and the powder content is also inconsistent). In general, because the volume of the activated carbon inside the canister varies, the gas filling space V inside the canister also varies. Under these circumstances, the pressure drop ΔP measured according to the ideal gas law is itself inaccurate.

[0016] 2. The preceding process for carbon canister testing is vibration friction welding. Vibration friction welding is a typical process where friction generates heat, causing the material to melt, followed by pressure welding. After welding, there is a noticeable temperature rise in some areas of the product. According to the ideal gas law, this temperature rise will have a significant impact on the testing process.

[0017] 3. Due to OBD technology, most China VI emission standard carbon canisters are equipped with a large atmospheric vent valve (CVS). The CVS works by using a coil to generate magnetic force that closes the valve core. When testing the airtightness of the carbon canister, power needs to be supplied to the CVS to close the atmospheric vent. During the power-on process, the CVS generates significant heat, which, similar to point 2 above, will also affect the testing process. Summary of the Invention

[0018] This invention provides a vehicle China VI carbon canister airtightness detection device that uses flow rate leakage measurement. Compared with the existing differential pressure method, it has high sensitivity, is suitable for small leakage amounts, can detect minute airflow changes, and is suitable for low pressure and micro-leak detection, thereby solving the problems mentioned in the background art.

[0019] The technical solution to the above problems is: a vehicle China VI carbon canister air tightness testing device, including a storage tank, a second regulating valve, a filling valve, a flow meter, a pressure sensor, a sensor valve, a temperature sensor, a standard tank, a bypass valve, a main pipeline, a branch pipeline, and a sealing and exhaust device;

[0020] The gas storage tank is connected in sequence to the second regulating valve, the charging valve, the sensor valve, and the adsorption port of the carbon canister via the main pipeline.

[0021] A branch pipe, connected in parallel with the main pipe, is provided between the inflation valve and the adsorption port; a standard tank and a bypass valve are installed on the branch pipe; the standard tank is connected to the bypass valve through the branch pipe; a temperature sensor is installed between the bypass valve and the adsorption port; the temperature sensor is installed on the main pipe; a flow meter and a pressure sensor are installed between the standard tank and the sensor valve; the flow meter and pressure sensor are installed on the main pipe.

[0022] The sealing and venting device is installed on the desorption port of the carbon canister.

[0023] A further technical solution is that a filter is installed between the gas storage tank and the second regulating valve, and the filter is installed on the main pipeline.

[0024] A further technical solution is that the gas storage tank is connected to the gas source through a first regulating valve.

[0025] The further technical solution is that the inflation valve, sensor valve and bypass valve are all shut-off valves.

[0026] A further technical solution is that the capacity of the gas storage tank is 5 to 10 L.

[0027] The further technical solution is that the capacity of the standard tank is 2L.

[0028] The further technical solution is that the pressure sensor has a range of 0-30 kPa and an accuracy of ±2%FS.

[0029] The further technical solution is that the flow meter has a range of 0-50 ml / min and an accuracy of ±2%FS.

[0030] By adopting the above technical solution, the automobile China VI carbon canister airtightness testing device of this utility model has the following advantages compared with the prior art:

[0031] This utility model discloses an automotive China VI emission standard carbon canister airtightness testing device that uses flow rate leakage detection. If the tested workpiece (carbon canister) has a leak, the pressure difference between the inner cavity of the tested workpiece (carbon canister) and the standard canister 10 will cause gas to flow from the standard canister 10 to the tested workpiece. The flow rate of the gas flowing through the flow meter 6, after calibration and conversion, can directly display the leakage value. Compared with the traditional differential pressure method, it has high sensitivity, is suitable for small leakage amounts, can detect minute airflow changes, and is suitable for low-pressure and micro-leak detection. Moreover, the flow rate leakage detection has a fast response and can provide leakage data quickly. In the same detection time, compared with the longer stabilization time required by differential pressure detection, this device has a relatively longer detection time and can obtain more data, providing more evidence for whether the product is qualified.

[0032] The technical features of a vehicle China VI carbon canister airtightness testing device of this utility model will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0033] Figure 1 is a schematic diagram of the connection between the automobile China VI carbon canister airtightness testing device and the carbon canister according to this utility model.

[0034] In the picture:

[0035] 1-First regulating valve, 2-Gas storage tank, 3-Filter, 4-Second pressure regulating valve, 5-Inflation valve, 6-Flow meter, 7-Pressure sensor, 8-Sensor valve, 9-Temperature sensor, 10-Standard tank, 11-Bypass valve, 12-Sealing exhaust device, 13-Adsorption port, 14-Desorption port, 15-Atmospheric port, 16-Carbon canister. Ⅰ-Main pipeline, Ⅱ-Branch pipeline. Detailed Implementation

[0036] As shown in Figure 1, an airtightness testing device for a China VI emission standard carbon canister includes an air storage tank 2, a second regulating valve 4, an inflation valve 5, a flow meter 6, a pressure sensor 7, a sensor valve 8, a temperature sensor 9, a standard tank 10, a bypass valve 11, a main pipeline I, a branch pipeline II, and a sealing and exhaust device 12.

[0037] The gas storage tank 2 is connected in sequence to the second regulating valve 4, the inflation valve 5, the sensor valve 8, and the adsorption port 13 of the carbon canister 16 via the main pipeline I. The gas outlet of the gas storage tank 2 is connected to the main pipeline I.

[0038] A branch pipe II, connected in parallel with the main pipe I, is provided between the inflation valve 5 and the adsorption port 13. A standard tank 10 and a bypass valve 11 are installed on the branch pipe II. The inlet and outlet of the standard tank 10 are both connected to the branch pipe II. The standard tank 10 is connected to the bypass valve 11 via the branch pipe II. A temperature sensor 9 is installed between the bypass valve 11 and the adsorption port 13. The temperature sensor 9 is installed on the main pipe I. A flow meter 6 and a pressure sensor 7 are installed between the standard tank 10 and the sensor valve 8. The flow meter 6 and the pressure sensor 7 are installed on the main pipe I. The temperature sensor 9 is used to monitor the carbon canister vent valve (CVS) until the heating temperature stabilizes, and then compares the reading with the flow meter 6. The flow meter 6 is used to detect the airflow rate to determine if there is a leak in the tested workpiece. The pressure sensor 7 is used to detect the pressure in the main pipe I to ensure that the inflation pressure is within the rated inflation pressure.

[0039] The sealing and venting device 12 is installed on the desorption port 14 of the carbon canister 16.

[0040] In order to remove dust, solid particles, water droplets and oil droplets from the gas and prevent them from entering subsequent equipment, a filter 3 is provided between the gas storage tank 2 and the second regulating valve 4, and the filter 3 is installed on the main pipeline I.

[0041] In this embodiment, the air inlet of the gas storage tank 2 is connected to the gas source through the first regulating valve 1, and the gas source is used to supply gas to the gas storage tank 2.

[0042] The inflation valve 5, sensor valve 8, and bypass valve can all be shut-off valves.

[0043] The capacity of the air storage tank 2 is 5-10L, mainly to provide a buffer during airflow loading. Because the air storage tank contains stored air pressure, the equipment's flow rate starts up more quickly and the continuous flow rate is more stable, effectively preventing pressure changes in the external compressed air pipeline from affecting the detection device. In principle, the larger the capacity of the air storage tank, the better; the selection of 5-10L is primarily based on a comprehensive consideration of the equipment's capacity and the effect of stable flow rate.

[0044] The standard canister has a capacity of 2L, mainly because the internal volume of the carbon canister is about 2L, and a similar standard canister volume can effectively reduce measurement errors.

[0045] The pressure sensor 7 has a range of 0-30 kPa and an accuracy of ±2%FS.

[0046] The flow meter 6 has a range of 0-50 ml / min and an accuracy of ±2%FS.

[0047] This invention relates to a testing method for an automotive China VI emission standard carbon canister airtightness testing device, the testing method comprising the following steps:

[0048] A. Connect the carbon canister 16 to be tested; that is, connect the end of the main pipe I of this device to the adsorption port 13 of the carbon canister 16; connect the sealing and exhaust device 12 to the desorption port 14 of the carbon canister 16.

[0049] B. Before testing, purge the inner cavity of carbon canister 16 to reduce the impact of the significant localized temperature rise caused by the vibration and friction welding process preceding the carbon canister 16 inspection on the pressure; the specific steps are as follows:

[0050] B1: Adjust the second pressure regulating valve 4 to the specified pressure (14-18 kPa), close the sensor valve 8, and open the charging valve 5, bypass valve 11, and carbon canister sealing device 12; at this time, the desorption port 14 of the carbon canister 16 is connected to the outside air; the atmospheric port 15 of the carbon canister 16 is in the open state.

[0051] B2: Open the first regulating valve 1. The air source continuously blows air through this airtightness detection device to cool down the carbon canister 16. After the carbon canister 16 cools down to the normal temperature, the purging ends and the carbon canister sealing device 12 is closed. At this time, the desorption port 14 of the carbon canister 16 is in the closed state.

[0052] C. Power on the CVS and close the atmospheric port 15 of the carbon canister 16.

[0053] D. Inflate the inner cavities of standard canister 10 and carbon canister 16 with air; after pressure sensor 7 shows that the rated inflation pressure has been reached, close inflation valve 5, stabilize for a period of time, temperature sensor 9 monitors the airflow temperature near CVS, and start detection when the temperature is constant.

[0054] E. Close the bypass valve 11 and open the sensor valve 8 to enter the measurement stage. If there is a leak in the carbon canister 16 being measured, the gas will flow from the standard canister 10 to the inner cavity of the carbon canister 16 during the measurement stage due to the pressure difference between the inner cavity of the carbon canister 16 and the standard canister 10 (if there is a leak, the pressure in the inner cavity of the carbon canister 16 is less than the pressure in the standard canister). Finally, the leakage value can be directly displayed by the airflow through the flow meter 6 after calibration and conversion.

[0055] All parts not covered in this utility model are the same as or can be implemented using existing technology. The above description is a further detailed explanation of this utility model in conjunction with specific preferred embodiments. It should not be construed that the specific implementation of this utility model is limited to the descriptions of the above embodiments. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of this utility model, and all such deductions or substitutions should be considered as falling within the patent protection scope defined by the submitted claims.

Claims

1. A device for testing the airtightness of a carbon canister for automobiles meeting China VI emission standards, characterized in that: The system includes a gas storage tank, a second regulating valve, a charging valve, a flow meter, a pressure sensor, a sensor valve, a temperature sensor, a standard tank, a bypass valve, a main pipeline, branch pipelines, and a sealing and venting device. The gas storage tank is connected sequentially to the second regulating valve, the charging valve, the sensor valve, and the adsorption port of the carbon canister via the main pipeline. A branch pipeline, connected in parallel with the main pipeline, is provided between the charging valve and the adsorption port. The standard tank and the bypass valve are installed on the branch pipeline. The standard tank is connected to the bypass valve via the branch pipeline. A temperature sensor is installed between the bypass valve and the adsorption port. The temperature sensor is installed on the main pipeline. A flow meter and a pressure sensor are installed between the standard tank and the sensor valve. The flow meter and pressure sensor are installed on the main pipeline. The sealing and venting device is installed at the desorption port of the carbon canister.

2. The vehicle China VI carbon canister airtightness testing device according to claim 1, characterized in that: A filter is installed between the gas storage tank and the second regulating valve, and the filter is installed on the main pipeline.

3. The vehicle China VI carbon canister airtightness testing device according to claim 1, characterized in that: The gas storage tank is connected to the gas source via a first regulating valve.

4. The vehicle China VI carbon canister airtightness testing device according to claim 1, characterized in that: The inflation valve, sensor valve, and bypass valve are all shut-off valves.

5. The vehicle China VI carbon canister airtightness testing device according to claim 1, characterized in that: The capacity of the gas storage tank is 5 to 10 liters.

6. The vehicle China VI carbon canister airtightness testing device according to claim 1, characterized in that: The standard tank has a capacity of 2L.

7. The vehicle China VI carbon canister airtightness testing device according to claim 1, characterized in that: The pressure sensor has a range of 0-30 kPa and an accuracy of ±2%FS.

8. The vehicle China VI carbon canister airtightness testing device according to claim 1, characterized in that: The flow meter has a range of 0-50 ml / min and an accuracy of ±2%FS.

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