Test method for fuel quantity calibration of aviation fuel tank

Abstract

The invention discloses a test method for fuel quantity calibration of an aviation fuel tank, and the method comprises the steps: measuring the fuel quantity of the aviation fuel tank on the ground, connecting a sensor to the aviation fuel tank, and recording a full fuel level voltage value when the aviation fuel tank is full of the fuel level; oil drainage operation is conducted on the aviation fuel tank with the full oil level, and the voltage value change range of the sensor and the available fuel amount of the aviation fuel tank are recorded; fuel calibration and indication testing are conducted on the aviation fuel tanks on the left side and the right side on the aircraft, and the zero fuel level and the full fuel level of the avionics displayer are calibrated according to the voltage value change range of the sensor; carrying out calibration test on the aviation fuel tank scales; according to the invention, the available fuel quantity of the aviation fuel tank and the full fuel level and the zero fuel level of the aviation fuel tank are measured on the ground, and the zero fuel level and the full fuel level are converted into corresponding voltage value ranges for calibration and are used for calibration of fuel quantity display of the aviation fuel tank on an avionics display.

Description

Technical Field

[0001] This invention relates to the field of testing aviation fuel tanks, and more particularly to a test method for calibrating the fuel quantity of aviation fuel tanks. Background Technology

[0002] Fuel gauges are a crucial part of an aircraft's fuel system, monitoring and displaying fuel levels in real time. Flight crews rely on these gauges to determine remaining fuel and make critical decisions (such as range extension, diversion, or emergency landing). Inaccurately calibrated systems can lead to erroneous readings. Furthermore, to verify compliance with airworthiness regulations, it is necessary to measure and calculate the available and unavailable fuel levels in the fuel tanks. Therefore, aviation fuel tank calibration is not optional but a periodic maintenance task essential for ensuring core elements of flight safety, meeting mandatory regulations, guaranteeing operational economy, and improving operational efficiency.

[0003] To address this need, this application proposes a solution. Summary of the Invention

[0004] Purpose of the invention: The purpose of this invention is to provide a test method for calibrating the fuel quantity in aviation fuel tanks, which can cover the calibration and testing of fuel quantity related to fuel systems, and is applicable to ground and airborne tests of fuel systems for light aircraft and sport aircraft.

[0005] Technical solution: The present invention provides a test method for calibrating the fuel quantity of an aviation fuel tank, specifically including the following steps:

[0006] S1: Measure the amount of fuel in the aviation fuel tank on the ground. After connecting a sensor to the aviation fuel tank, record the full fuel level voltage value when the aviation fuel tank is full.

[0007] S2: Perform fuel draining operation on a full aviation fuel tank, record the range of sensor voltage changes and the amount of available fuel in the aviation fuel tank;

[0008] S3: Perform fuel calibration and indication tests on the left and right fuel tanks on the aircraft respectively, and calibrate the zero fuel level and full fuel level of the avionics display based on the range of sensor voltage changes obtained in S2.

[0009] S4: Perform a calibration test on the aviation fuel tank scale. The calibration test is conducted simultaneously with the tests in S1, S2, or S3.

[0010] Preferably, step S1 specifically includes the following steps:

[0011] S1.1: Secure the aviation fuel tank to the test bench and close the fuel return port, drain valve, and ball valve of the aviation fuel tank;

[0012] S1.2: Add a predetermined amount of fuel to the aviation fuel tank until it is close to the maximum level, then slowly fill it to the full level;

[0013] S1.3: The sensor detects and records the full fuel level voltage value of the aviation fuel tank when it is full.

[0014] Preferably, step S2 specifically includes the following steps:

[0015] S2.1: Open the ball valve of the aviation fuel tank to start discharging fuel, and the sensor starts to continuously record the voltage changes of the aviation fuel tank;

[0016] S2.2: When the voltage value detected by the sensor no longer changes, stop discharging fuel and record the voltage value at this time, which is the zero fuel level voltage value of the aviation fuel tank. Obtain the range value from the full fuel level voltage value to the zero fuel level voltage value of the aviation fuel tank. The amount of fuel discharged during this stage is the amount of usable fuel.

[0017] Preferably, the sensor is a capacitive fuel level sensor.

[0018] Preferably, step S3 specifically includes the following steps:

[0019] S3.1: After the aviation fuel tanks are installed on the aircraft, connect the pipeline, turn on the avionics display, and ensure that the aviation fuel tank on the left is connected and the aviation fuel tank on the right is disconnected.

[0020] S3.2: Add fuel to the aviation fuel tank. When the aviation fuel tank display reading begins to change, record the amount of fuel added at this time, X. Calibrate the avionics display to zero fuel level. The amount of fuel added, X, is the amount of undetectable fuel in the aviation fuel tank.

[0021] S3.3: Starting from zero fuel level, gradually add equal amounts of fuel to the aviation fuel tank on the avionics display until the aviation fuel tank is full, and record the change in the avionics display reading Y during this process;

[0022] S3.4: Read the fuel tank voltage value from the avionics display interface during the process of the fuel tank going from zero fuel level to full fuel level;

[0023] S3.5: After converting the read voltage value to the corresponding fuel quantity, subtract the refueling quantity X to obtain the fuel quantity Z that should be displayed on the avionics display screen in the aviation fuel tank;

[0024] S3.6: Compare Y and Z. When Y and Z are consistent, it indicates that the avionics display reading is accurate. When Y and Z are inconsistent, the avionics display reading should be calibrated.

[0025] S3.7: Disconnect the left aviation fuel tank and connect the right aviation fuel tank. Repeat the process of S3.2-S3.6 to complete the fuel calibration and indication test of the left and right aviation fuel tanks on the avionics display.

[0026] As a preferred option, the range of aviation fuel tank voltage values ​​read from the avionics display interface in S3.4 is compared with the range of voltage values ​​obtained in S2 to complete the secondary verification of the aviation fuel tank voltage range.

[0027] Preferably, in the secondary test, the voltage value change and the fuel level displayed on the avionics display are compared to see whether they change linearly. If they do, the test is normal; if not, troubleshooting is performed.

[0028] Preferably, step S4 specifically includes the following steps:

[0029] S4.1: When injecting or releasing an equal amount of fuel in S1, S2 or S3, or when the avionics display shows a change in the fuel quantity reading, perform fuel quantity calibration by marking lines on the outer shell of the aviation fuel tank.

[0030] S4.2: After marking and printing the scale paper according to the calibrated fuel quantity, paste the scale paper on the observation window of the fuel tank to indicate the real-time fuel quantity to the crew.

[0031] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0032] 1. This invention measures the available fuel quantity of aviation fuel tanks and the full and zero fuel levels on the ground, and converts the zero and full fuel levels into corresponding voltage ranges for calibration. This is used to calibrate the fuel quantity display on the avionics display of aviation fuel tanks. The test method is simple to operate, requires no customized tooling or equipment, and all products are off-the-shelf and easy to purchase. In addition, the electrical connection harnesses are clearly marked to prevent misconnection.

[0033] 2. The test results of the test method of the present invention are accurate and can be mutually verified. When calibrated on the machine, the ground test data can be compared. If the deviation is large, troubleshooting can be carried out in time and the normal operation of each connected device can be checked.

[0034] 3. The test method of this invention is a general method with simple process specifications. It adopts a quantitative oiling method to observe pressure changes, and the results are intuitive and easy for assembly workers to operate.

[0035] 4. The test method of the present invention can be carried out by adding oil or by draining oil, which can effectively avoid repeated draining causing fuel waste and shorten the test time;

[0036] 5. The testing method of this invention is highly flexible, and the testing sequence can be adjusted according to the production plan. Tests can be conducted individually, and two tests on the machine can be conducted continuously or simultaneously, shortening the testing steps and greatly reducing the workload of operators. Attached Figure Description

[0037] Figure 1 This is a diagram of the ground fuel tank calibration test in this invention.

[0038] Figure 2 This is the electrical schematic diagram of the oil level sensor in this invention.

[0039] Figure 3 This is a diagram showing the calibration pipeline connection of the aircraft fuel tank in this invention.

[0040] Figure 4 This is the fuel calibration record table in this invention. Detailed Implementation

[0041] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0042] See appendix Figures 1-4 The figure illustrates the test method for calibrating the fuel quantity in an aviation fuel tank according to the present invention, which specifically includes the following steps:

[0043] S1: Measure the fuel level in the aviation fuel tank on the ground. After connecting a capacitive fuel level sensor to the aviation fuel tank, record the full fuel level voltage value when the fuel tank is full. This includes the following steps:

[0044] S1.1: Secure the aviation fuel tank to the test bench and close the fuel return port, drain valve, and ball valve of the aviation fuel tank;

[0045] S1.2: Add a predetermined amount of fuel to the aviation fuel tank until it is close to the maximum level, then slowly fill it to the full level;

[0046] S1.3: The capacitive fuel level sensor detects and records the full fuel level voltage value of the aviation fuel tank when it is full.

[0047] S2: Perform a fuel draining operation on a full aviation fuel tank, record the voltage change range of the capacitive fuel level sensor and the available fuel quantity in the aviation fuel tank, specifically including the following steps:

[0048] S2.1: Open the ball valve of the aviation fuel tank to start releasing fuel, and the capacitive fuel level sensor starts to continuously record the voltage changes of the aviation fuel tank;

[0049] S2.2: When the voltage value detected by the sensor no longer changes, stop discharging fuel and record the voltage value at this time, which is the zero fuel level voltage value of the aviation fuel tank. Obtain the range value from the full fuel level voltage value to the zero fuel level voltage value of the aviation fuel tank. The amount of fuel discharged during this stage is the amount of usable fuel.

[0050] S3: Perform fuel calibration and indication tests on the left and right fuel tanks on board. Based on the voltage change range of the capacitive fuel level sensor obtained in S2, calibrate the zero fuel level and full fuel level of the avionics display. This includes the following steps:

[0051] S3.1: After the aviation fuel tanks are installed on the aircraft, connect the pipeline, turn on the avionics display, and ensure that the aviation fuel tank on the left is connected and the aviation fuel tank on the right is disconnected.

[0052] S3.2: Fill the aviation fuel tank with fuel. Wait until the fuel tank display reading begins to change, such as... Figure 4 The fuel level X is recorded in the fuel calibration record table. The fuel level X is the undetectable fuel level in the fuel tank, including fuel levels that cannot be detected by sensors, such as fuel in pipelines, fuel levels below zero, and fuel tank dead fuel. The avionics display is calibrated to zero fuel level.

[0053] S3.3: Starting from zero fuel level, gradually add 5L of fuel to the aviation fuel tank on the avionics display until the aviation fuel tank is full. At this time, the amount of fuel added is 50+X. Record the change of the avionics display reading Y during this process. When the aviation fuel tank is full, the avionics display shows a reading Y of 50.

[0054] S3.4: Read the fuel tank voltage value from the avionics display interface during the process of the fuel tank going from zero fuel level to full fuel level;

[0055] S3.5: After converting the read voltage value to the corresponding fuel quantity, subtract the refueling quantity X to obtain the fuel quantity Z that should be displayed on the avionics display screen in the aviation fuel tank;

[0056] S3.6: Compare Y and Z. When Y and Z are consistent, it indicates that the avionics display reading is accurate. When Y and Z are inconsistent, the avionics display reading should be calibrated.

[0057] S3.7: Disconnect the left aviation fuel tank and connect the right aviation fuel tank. Repeat the process of S3.2-S3.6 to complete the fuel calibration and indication test of the left and right aviation fuel tanks on the avionics display.

[0058] S4: Perform a calibration test on the aviation fuel tank scale. The calibration test is conducted simultaneously with the tests in S1, S2, or S3. Specifically:

[0059] S4.1: When injecting or releasing an equal amount of fuel in S1, S2 or S3, or when the avionics display shows a change in the fuel quantity reading, perform fuel quantity calibration by marking lines on the outer shell of the aviation fuel tank.

[0060] S4.2: After marking and printing the scale paper according to the calibrated fuel quantity, paste the scale paper on the observation window of the fuel tank to indicate the real-time fuel quantity to the crew.

[0061] In this embodiment, it is necessary to compare the range of aviation fuel tank voltage values ​​read from the avionics display interface in S3.4 with the range of voltage values ​​obtained in S2 to complete the secondary verification of the aviation fuel tank voltage range. In the secondary verification, the voltage value change and whether the fuel quantity displayed on the avionics display changes linearly are compared. If so, it is normal; if not, troubleshooting is performed.

Claims

1. A test method for calibrating the fuel quantity in an aviation fuel tank, characterized in that: Specifically, the following steps are included: S1: Measure the amount of fuel in the aviation fuel tank on the ground. After connecting a sensor to the aviation fuel tank, record the full fuel level voltage value when the aviation fuel tank is full. S2: Perform fuel draining operation on a full aviation fuel tank, record the range of sensor voltage changes and the amount of available fuel in the aviation fuel tank; S3: Perform fuel calibration and indication tests on the left and right fuel tanks on the aircraft respectively, and calibrate the zero fuel level and full fuel level of the avionics display based on the range of sensor voltage changes obtained in S2. S4: Perform a calibration test on the aviation fuel tank scale. The calibration test is conducted simultaneously with the tests in S1, S2, or S3.

2. The test method for calibrating the fuel quantity of an aviation fuel tank according to claim 1, characterized in that: S1 specifically includes the following steps: S1.1: Secure the aviation fuel tank to the test bench and close the fuel return port, drain valve, and ball valve of the aviation fuel tank; S1.2: Add a predetermined amount of fuel to the aviation fuel tank until it is close to the maximum level, then slowly fill it to the full level; S1.3: The sensor detects and records the full fuel level voltage value of the aviation fuel tank when it is full.

3. The test method for calibrating the fuel quantity of an aviation fuel tank according to claim 1, characterized in that: S2 specifically includes the following steps: S2.1: Open the ball valve of the aviation fuel tank to start discharging fuel, and the sensor starts to continuously record the voltage changes of the aviation fuel tank; S2.2: When the voltage value detected by the sensor no longer changes, stop discharging fuel and record the voltage value at this time, which is the zero fuel level voltage value of the aviation fuel tank. Obtain the range value from the full fuel level voltage value to the zero fuel level voltage value of the aviation fuel tank. The amount of fuel discharged during this stage is the amount of usable fuel.

4. The test method for calibrating the fuel quantity of an aviation fuel tank according to claim 1, characterized in that: The sensor is a capacitive fuel level sensor.

5. The test method for calibrating the fuel quantity of an aviation fuel tank according to claim 1, characterized in that: S3 specifically includes the following steps: S3.1: After the aviation fuel tanks are installed on the aircraft, connect the pipeline, turn on the avionics display, and ensure that the aviation fuel tank on the left is connected and the aviation fuel tank on the right is disconnected. S3.2: Add fuel to the aviation fuel tank. When the aviation fuel tank display reading begins to change, record the amount of fuel added at this time, X. Calibrate the avionics display to zero fuel level. The amount of fuel added, X, is the amount of undetectable fuel in the aviation fuel tank. S3.3: Starting from zero fuel level, gradually add equal amounts of fuel to the aviation fuel tank on the avionics display until the aviation fuel tank is full, and record the change in the avionics display reading Y during this process; S3.4: Read the fuel tank voltage value from the avionics display interface during the process of the fuel tank going from zero fuel level to full fuel level; S3.5: After converting the read voltage value to the corresponding fuel quantity, subtract the refueling quantity X to obtain the fuel quantity Z that should be displayed on the avionics display screen in the aviation fuel tank; S3.6: Compare Y and Z. When Y and Z are consistent, it indicates that the avionics display reading is accurate. When Y and Z are inconsistent, the avionics display reading should be calibrated. S3.7: Disconnect the left aviation fuel tank and connect the right aviation fuel tank. Repeat the process of S3.2-S3.6 to complete the fuel calibration and indication test of the left and right aviation fuel tanks on the avionics display.

6. The test method for calibrating the fuel quantity of an aviation fuel tank according to claim 5, characterized in that: Compare the range of aviation fuel tank voltage values ​​read from the avionics display interface in S3.4 with the range of voltage values ​​obtained in S2 to complete the secondary verification of the aviation fuel tank voltage range.

7. The test method for calibrating the fuel quantity of an aviation fuel tank according to claim 6, characterized in that: The secondary test compares the voltage change and whether the fuel level displayed on the avionics display changes linearly. If so, it is normal; otherwise, troubleshooting is performed.

8. The test method for calibrating the fuel quantity of an aviation fuel tank according to claim 1, characterized in that: S4 specifically includes the following steps: S4.1: When injecting or releasing an equal amount of fuel in S1, S2 or S3, or when the avionics display shows a change in the fuel quantity reading, perform fuel quantity calibration by marking lines on the outer shell of the aviation fuel tank. S4.2: After marking and printing the scale paper according to the calibrated fuel quantity, paste the scale paper on the observation window of the fuel tank to indicate the real-time fuel quantity to the crew.

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