A method for measuring fuel in a heterogeneous fuel tank

Abstract

The present invention discloses a fuel measurement method for a heterogeneous fuel tank. The upper ends of the heterogeneous fuel tanks are connected, and according to the unconnected parts at the lower ends of the heterogeneous fuel tanks, the heterogeneous fuel tanks are sequentially divided into several measurement units; several fuel quantity sensors are sequentially connected from top to bottom in the measurement unit. The fuel quantity sensors are divided into three sections from top to bottom: upper non-measurable, normal oil immersion, and lower non-measurable. Each fuel quantity sensor is provided with a fuel mass characteristic database corresponding to the oil level height and the fuel quantity. The fuel quantity corresponding to the oil level height of the fuel quantity sensors in each measurement unit is obtained, and the fuel quantities of all measurement units are summed to obtain the fuel quantity of the heterogeneous fuel tank. By splitting the heterogeneous fuel tank into several measurement units, the present invention can quickly and accurately obtain the fuel quantity of the entire heterogeneous fuel tank through the fuel quantity measurement of each measurement unit, effectively improving the test efficiency. Moreover, the measurement error of the fuel quantity in the fuel tank is relatively small compared with the prior art, meeting the requirements of practical use and having good practicability.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel measurement methods, and particularly relates to a fuel measurement method for a heterogeneous fuel tank. Background Art

[0002] Fuel quantity measurement can provide accurate information on the fuel quantity in the aircraft fuel tank for the pilot, which plays an important role in enabling the pilot to make correct flight judgments in real time. With the development and progress of science and technology, the requirements for the accuracy, stability, and reliability of fuel quantity measurement are getting higher and higher. However, due to the needs of the overall balance and counterweight of the aircraft, matching the shape of the intake duct, and equipment layout, the fuel tank may be designed in various shapes to meet the aircraft layout requirements. For example, Figure 1 a fuel tank structure shown with an approximately horseshoe shape bifurcating downward and fuel quantity sensors arranged vertically, which requires the software algorithm to process different measurement states of the fuel quantity sensors accordingly. Summary of the Invention

[0003] The purpose of the present invention is to provide a fuel measurement method for a heterogeneous fuel tank, aiming to measure the fuel quantity in the heterogeneous fuel tank. The present invention provides a fuel quantity selection and processing method covering various measurement states for irregularly shaped fuel tanks to solve the problem of large jumps in the fuel quantity display of heterogeneous fuel tanks and prevent large jumps in the fuel quantity due to software logic defects.

[0004] The present invention is mainly implemented through the following technical solutions:

[0005] A fuel measurement method for a heterogeneous fuel tank, where the upper ends of the heterogeneous fuel tanks are connected, and the heterogeneous fuel tank is sequentially divided into several measurement units according to the non-connected parts at the lower ends of the heterogeneous fuel tanks; several fuel quantity sensors are sequentially connected from top to bottom in the measurement unit, and the fuel quantity sensors are divided into three sections from top to bottom: upper non-measurable, normal oil immersion, and lower non-measurable. Each fuel quantity sensor is provided with a fuel mass characteristic database corresponding to the oil level height and the fuel quantity; the fuel quantity corresponding to the oil level height of the fuel quantity sensor in each measurement unit is obtained, and the fuel quantities of all measurement units are summed to obtain the fuel quantity of the heterogeneous fuel tank.

[0006] To better implement the present invention, further, in the measurement unit, among adjacent fuel quantity sensors, if the oil level of the upper fuel quantity sensor is in the lower non-measurable section and the oil level of the lower fuel quantity sensor is in the upper non-measurable or normal oil immersion section, the fuel quantity corresponding to the measurement unit is obtained by querying the fuel mass characteristic database with the oil level height of the lower fuel quantity sensor.

[0007] To better implement the present invention, further, in the measurement unit, among adjacent fuel quantity sensors, if the oil level of the upper fuel quantity sensor is in the non-measurable upper or normal immersion section, and the oil level of the lower fuel quantity sensor is in the non-measurable upper section, then the fuel quantity corresponding to the measurement unit is obtained by querying the fuel quality characteristic database with the oil level height of the upper fuel quantity sensor.

[0008] To better implement the present invention, further, in the measurement unit, among adjacent fuel quantity sensors, if the oil level of the upper fuel quantity sensor is in the non-measurable upper or normal immersion section, and the oil level of the lower fuel quantity sensor is in the normal immersion section or the non-measurable lower section, then the measured fuel quantity of the upper fuel quantity sensor is obtained by querying the fuel quality characteristic database with the oil level height of the upper fuel quantity sensor, and the actual measured fuel quantity of the upper fuel quantity sensor is obtained by subtracting the range of the lower fuel quantity sensor from it. Then, the measured fuel quantity of the lower fuel quantity sensor obtained by querying the fuel quality characteristic database with the oil level height of the lower fuel quantity sensor is added to obtain the fuel quantity corresponding to the measurement unit.

[0009] To better implement the present invention, further, in the measurement unit, among adjacent fuel quantity sensors, if the oil level of the upper fuel quantity sensor is in the non-measurable lower section, and the oil level of the lower fuel quantity sensor is in the non-measurable lower section, then the fuel quantity is set to zero.

[0010] To better implement the present invention, further, the ranges of the non-measurable upper and non-measurable lower sections of the fuel quantity sensor are the error allowable ranges of the fuel quantity sensor.

[0011] To better implement the present invention, further, the heterogeneous fuel tank is successively divided into several measurement units according to the number of non-connected inner closed bottom surfaces at the lower end of the heterogeneous fuel tank.

[0012] Advantages of the present invention:

[0013] By splitting the heterogeneous fuel tank into several measurement units, the present invention can quickly and accurately obtain the fuel quantity of the entire heterogeneous fuel tank through the fuel quantity measurement of each measurement unit, effectively improving the test efficiency. Moreover, the measurement error of the fuel tank fuel quantity is relatively small compared with the prior art, meeting the requirements of practical use and having good practicability. Description of the Drawings

[0014] Figure 1 Schematic structural diagram of dividing measurement units for a bifurcated horseshoe-shaped heterogeneous fuel tank;

[0015] Figure 2 Schematic structural diagram of dividing measurement units for a U-shaped horseshoe-shaped heterogeneous fuel tank;

[0016] Figure 3 Schematic diagram of fuel quantity sensor segmentation;

[0017] Figure 4 Schematic diagram showing the oil level height when neither the upper nor the lower oil quantity sensor is immersed in oil;

[0018] Figure 5 Schematic diagram showing the oil level height when the lower oil quantity sensor is normally immersed in oil and the upper part of the upper oil quantity sensor is not measurable;

[0019] Figure 6 Schematic diagram showing the oil level height when the upper part of the lower oil quantity sensor is not measurable and the upper part of the upper oil quantity sensor is not measurable;

[0020] Figure 7 Schematic diagram showing the oil level height when the upper part of the lower oil quantity sensor is not measurable and the upper oil quantity sensor is normally immersed in oil;

[0021] Figure 8 Schematic diagram showing the oil level height when both the upper and lower oil quantity sensors are in the state where the upper part is not measurable;

[0022] Figure 9 Schematic diagram showing the oil level height when both the upper and lower oil quantity sensors are in the normal immersion state;

[0023] Figure 10 Flow chart of the present invention. Detailed implementation manners

[0024] Example 1:

[0025] A fuel measurement method for a heterogeneous fuel tank, as Figures 1 - 3 shown, the upper ends of the heterogeneous fuel tanks are connected, and the heterogeneous fuel tank is sequentially divided into several measurement units according to the non - connected parts at the lower ends of the heterogeneous fuel tanks; several oil quantity sensors are sequentially connected from top to bottom in the measurement unit, and the oil quantity sensors are divided into three sections from top to bottom: the upper part is not measurable, normal immersion, and the lower part is not measurable. Each oil quantity sensor is provided with a fuel mass characteristic database corresponding to the oil level height and the oil quantity; the oil quantity corresponding to the oil level height of the oil quantity sensor in each measurement unit is obtained, and the oil quantities of all measurement units are summed to obtain the fuel quantity of the heterogeneous fuel tank.

[0026] By splitting the heterogeneous fuel tank into several measurement units, the present invention can quickly and accurately obtain the fuel quantity of the entire heterogeneous fuel tank through the oil quantity measurement of each measurement unit, effectively improving the test efficiency. Moreover, the measurement error of the fuel quantity in the fuel tank is relatively small compared with the prior art, meeting the requirements of practical use and having good practicability.

[0027] Example 2:

[0028] This embodiment is optimized based on Embodiment 1. In the measurement unit, among adjacent fuel quantity sensors, if the oil level of the upper fuel quantity sensor is in the lower non-measurable section and the oil level of the lower fuel quantity sensor is in the upper non-measurable or normal immersion section, the fuel quantity corresponding to the measurement unit is obtained by querying the fuel quality characteristic database with the oil level height of the lower fuel quantity sensor.

[0029] Further, in the measurement unit, among adjacent fuel quantity sensors, if the oil level of the upper fuel quantity sensor is in the upper non-measurable or normal immersion section and the oil level of the lower fuel quantity sensor is in the upper non-measurable section, the fuel quantity corresponding to the measurement unit is obtained by querying the fuel quality characteristic database with the oil level height of the upper fuel quantity sensor.

[0030] Further, in the measurement unit, among adjacent fuel quantity sensors, if the oil level of the upper fuel quantity sensor is in the upper non-measurable or normal immersion section and the oil level of the lower fuel quantity sensor is in the normal immersion section or the lower non-measurable section, the measured fuel quantity of the upper fuel quantity sensor is obtained by querying the fuel quality characteristic database with the oil level height of the upper fuel quantity sensor, and then the measured fuel quantity of the upper fuel quantity sensor is obtained by subtracting the range of the lower fuel quantity sensor. Then, the measured fuel quantity of the lower fuel quantity sensor obtained by querying the fuel quality characteristic database with the oil level height of the lower fuel quantity sensor is added to obtain the fuel quantity corresponding to the measurement unit.

[0031] Further, in the measurement unit, among adjacent fuel quantity sensors, if the oil level of the upper fuel quantity sensor is in the lower non-measurable section and the oil level of the lower fuel quantity sensor is in the lower non-measurable section, the fuel quantity is set to zero.

[0032] Other parts of this embodiment are the same as those of Embodiment 1, so they will not be elaborated here.

[0033] Embodiment 3:

[0034] This embodiment is optimized based on Embodiment 1 or 2. The ranges of the upper non-measurable and lower non-measurable sections of the fuel quantity sensor are the error tolerance ranges of the fuel quantity sensor.

[0035] Further, as Figure 1 shown, the heterogeneous fuel tank is successively divided into several measurement units according to the number of non-connected inner closed bottom surfaces at the lower end of the heterogeneous fuel tank.

[0036] Other parts of this embodiment are the same as those of the above Embodiment 1 or 2, so they will not be elaborated here.

[0037] Embodiment 4:

[0038] A fuel measurement method for a heterogeneous fuel tank divides the heterogeneous fuel tank with non-connected lower ends into as few regular-shaped measurement units as possible; as Figure 3As shown in the figure, each fuel quantity sensor in the fuel tank is divided into three segments according to the immersion height of the aircraft fuel quantity sensor, namely the lower non-measurable segment, the normal immersion segment, and the upper non-measurable segment. After mapping different fuel surface postures to the immersion height of the fuel quantity sensor, the fuel quantity selection and processing method is determined according to different segment combinations of the fuel quantity sensors with different measurement states in the same measurement unit. If each fuel quantity sensor in the same unit measurement corresponds to a fuel mass characteristic database, then according to the foregoing method, the fuel mass characteristic database corresponding to one of the fuel quantity sensors is determined as the fuel mass characteristic database of this fuel tank for looking up the table to calculate the fuel quantity.

[0039] Further, when the fuel quantity sensors in the heterogeneous fuel tank are arranged vertically, if both the upper and lower fuel quantity sensors are in the lower non-measurable state, the fuel quantity is set to zero.

[0040] Further, when the fuel quantity sensors in the heterogeneous fuel tank are arranged vertically, if the upper fuel quantity sensor is not in the lower non-measurable state (normal immersion or upper non-measurable) and the lower fuel quantity sensor is in the upper non-measurable state, the fuel quantity queried from the database by the upper fuel quantity sensor is used as the fuel quantity of this fuel tank.

[0041] Further, when the fuel quantity sensors in the heterogeneous fuel tank are arranged vertically, if the upper fuel quantity sensor is in the lower non-measurable state and the lower fuel quantity sensor is not in the lower non-measurable state (normal immersion or upper non-measurable), the fuel quantity queried from the database by the lower fuel quantity sensor is used as the fuel quantity of this fuel tank.

[0042] Further, when the fuel quantity sensors in the heterogeneous fuel tank are arranged vertically, if the upper fuel quantity sensor is not in the lower non-measurable state (normal immersion or upper non-measurable) and the lower fuel quantity sensor is not in the upper non-measurable state (normal immersion or lower non-measurable), then its true measurement error is reflected in the fuel quantity, that is, the measured fuel quantity of the upper fuel quantity sensor (the difference between the fuel quantity queried in real time by the upper fuel quantity sensor and the fuel quantity queried at the top of the lower fuel quantity sensor in this fuel surface angle state) plus the fuel quantity queried in real time by the lower fuel quantity sensor is used as the fuel quantity of this fuel tank.

[0043] Further, when a fuel quantity sensor fails, this fuel quantity sensor is regarded as being in the lower non-measurable state.

[0044] Further, the upper non-measurable and lower non-measurable ranges of the fuel quantity sensor specifically refer to the error tolerance range of the fuel quantity sensor itself.

[0045] Further, the total fuel quantity of the heterogeneous fuel tank is the sum of the fuel quantities of each fuel quantity measurement unit measured by the foregoing method.

[0046] Further, if each fuel quantity sensor in the same measurement unit corresponds to a fuel mass characteristic database (immersion height, oil surface pitch angle, oil surface roll angle VS volume), after calculating the fuel volume by interpolation from the fuel mass characteristic database by combining the immersion height of the fuel quantity sensor with the oil surface attitude angle, according to the present invention, the fuel quantity is calculated based on the fuel volume calculated by looking up the table from the corresponding fuel mass characteristic database of one of the fuel quantity sensors.

[0047] If all fuel quantity sensors in a measurement unit correspond to a fuel mass characteristic database (reference height, oil surface pitch angle, oil surface roll angle VS volume), when the measurement state of the fuel quantity sensor is that the upper fuel quantity sensor is not measurable downward (normal immersion or not measurable upward) and the lower fuel quantity sensor is not measurable upward (normal immersion or not measurable downward), the immersion characterization height is calculated according to the projection relationship of each fuel quantity sensor, and the characterization oil surface height of the fuel tank is determined according to the present invention, and then the fuel quantity of the measurement unit is looked up and calculated.

[0048] The present invention can quickly and accurately obtain the fuel quantity of the entire heterogeneous fuel tank by splitting the heterogeneous fuel tank into several measurement units and measuring the fuel quantity of each measurement unit. The test efficiency is effectively improved, and the measurement error of the fuel quantity in the fuel tank is relatively small compared with the prior art, meeting the requirements of practical use and having good practicability.

[0049] Embodiment 5:

[0050] A method for measuring fuel in a heterogeneous fuel tank, as Figure 1 shown, the irregular heterogeneous fuel tank is divided into several relatively regular measurement units with non-flowing bottoms according to the number of closed bottom surfaces in the fuel tank; the number of measurement units depends on the number of bifurcations at the lower end of the fuel tank; each measurement unit can be different or asymmetric; each measurement unit is narrow and long and the fuel quantity sensors are arranged vertically; the heterogeneous fuel tank can be deformed according to the requirements of the on-board structure layout to increase or decrease the number of its bifurcations, and the bottom or top of each bifurcation of the fuel tank can be a plane, an inclined plane, or a curved surface, and the fuel tank wall can also be a plane, an inclined plane, or a curved surface.

[0051] Further, as Figure 10 shown, in the measurement unit, according to the effective length L of the fuel quantity sensor and the immersion height H of the fuel quantity sensor, the immersion state of the fuel quantity sensor is determined, and then the reference oil surface height HF is characterized, and the fuel quantity of the measurement unit is obtained by querying the fuel mass characteristic database of the fuel quantity sensor, and finally the total fuel quantity of the heterogeneous fuel tank is obtained by integrating the fuel quantities of each measurement unit.

[0052] Further, as Figure 2 shown, the heterogeneous fuel tank can be U-shaped or horseshoe-shaped, and the fuel tank is sequentially divided into a left fuel tank compartment and a right fuel tank compartment from left to right, and upper fuel quantity sensors and lower fuel quantity sensors are sequentially arranged in the left fuel tank compartment and the right fuel tank compartment from top to bottom.

[0053] Further, use numerical simulation software to generate a fuel mass characteristic database 1 (immersion height, oil surface pitch angle, oil surface roll angle VS volume) or a fuel mass characteristic database 2 (reference height, oil surface pitch angle, oil surface roll angle VS volume) for each measurement unit of the fuel tank.

[0054] Further, as Figure 3 shown, each fuel quantity sensor is divided into three segments from bottom to top: the area between AB is the non-measurable area below the fuel quantity sensor, and the specific value can refer to the allowable error range of the fuel quantity sensor; the area between BC is the normal immersion area of the fuel quantity sensor; the area between CD is the non-measurable area above the fuel quantity sensor, and the specific value can refer to the allowable error range of the fuel quantity sensor.

[0055] Further, as Figure 4 shown, when the fuel quantity is too low for the fuel quantity sensor to be immersed, that is, both the upper and lower fuel quantity sensors are in the non-measurable state below, the reference height of this measurement unit is set to 0 and the fuel quantity is set to 0.

[0056] Further, as Figure 5 shown, when the lower fuel quantity sensor is normally immersed and the upper fuel quantity sensor is non-measurable below, the reference height of this measurement unit takes the reference height of the lower fuel quantity sensor, and the fuel quantity also takes the value obtained by looking up the table of the lower fuel quantity sensor.

[0057] Further, as Figure 6 shown, when the lower fuel quantity sensor is non-measurable above and the upper fuel quantity sensor is non-measurable below, the reference height of this measurement unit takes the reference height of the lower fuel quantity sensor, and the fuel quantity also takes the value obtained by looking up the table of the lower fuel quantity sensor.

[0058] Further, as Figure 7 shown, when the lower fuel quantity sensor is non-measurable above and the upper fuel quantity sensor is normally immersed, the reference height of this measurement unit takes the reference height of the upper fuel quantity sensor, and the fuel quantity also takes the value obtained by looking up the table of the upper fuel quantity sensor.

[0059] Further, as Figure 8 shown, when the fuel quantity is too full for the fuel quantity sensors to be immersed, that is, both the upper and lower fuel quantity sensors are in the non-measurable state above, the reference height of this measurement unit takes the reference height of the upper fuel quantity sensor, and the fuel quantity also takes the value obtained by looking up the table of the upper fuel quantity sensor.

[0060] Further, as Figure 9As shown in the figure, when the fuel level sensor measures abnormally and both the upper and lower fuel level sensors are in a normal oil immersion state, since it is impossible to determine which fuel level sensor measures abnormally at this time, the fuel quantity can only be calculated based on the actual measurement values of each fuel level sensor at this time. The fuel quantity of this measurement unit = the fuel quantity looked up from the oil immersion point of the lower fuel level sensor + (the fuel quantity looked up from the oil immersion point of the upper fuel level sensor - the fuel quantity looked up from the top of the lower fuel level sensor); the basis for querying the fuel quality characteristic database can also be replaced by the fuel quantity at the reference height when the reference height is used.

[0061] The environmental basis for fuel quantity measurement is fuel, fuel level sensors, and sampling circuits. Among them, changes in the dielectric constant of fuel and sampling circuits may cause errors of different degrees in oil level measurement. For the measurement unit with the upper and lower fuel level sensors arranged, it may result in a situation of two or more oil levels. In such a contradictory situation, calculating errors of up to ±40% may occur no matter which oil level is adopted. In the prior art, in order to prevent flight accidents caused by false reporting of fuel quantity, if the lower fuel level sensor is in a state where it is impossible to measure upward (normal oil immersion or impossible to measure downward), the measured oil level of the lower fuel level sensor is adopted. In this way, the fuel quantity range measured by the upper fuel level sensor is ignored, and the calculation measurement error is: the fuel quantity measured by the upper fuel level sensor / the full fuel quantity of the measurement unit * 100%.

[0062] For example, a certain type of aircraft is equipped with a Figure 2 horseshoe-shaped fuel tank as shown in the figure. The measurement range of the lower fuel level sensor of a single measurement unit in the fuel tank is 0 - 194L, and the measurement range of the upper fuel level sensor is 195 - 301L. After the aircraft was delivered to the user, there was a situation where the indicated fuel quantity was about 772 pounds when the fuel tank was full (1027 pounds), and the error was about -25%. The reason was that due to changes in the dielectric constant of fuel and circuit measurement errors, the oil level measurement error of one of the fuel level sensors at the lower end of the fuel tank reached about -5%, resulting in it being determined to be in a normal oil immersion state. The present invention comprehensively considers the two measured oil levels. The measured fuel quantity error is also caused by environmental errors and will not generate new calculation errors. The verified measured value is 1020 pounds, and the error of the entire fuel tank fuel quantity is corrected to within 1%.

[0063] The present invention can quickly and accurately obtain the fuel quantity of the entire heterogeneous fuel tank by splitting the heterogeneous fuel tank into several measurement units and measuring the fuel quantity of each measurement unit. The test efficiency is effectively improved, and the measurement error of the fuel tank fuel quantity is relatively small compared with the prior art, meeting the requirements of practical use and having good practicability.

[0064] The above are only the preferred embodiments of the present invention and do not impose any form of limitation on the present invention. Any simple modification or equivalent change made to the above embodiments based on the technical essence of the present invention falls within the protection scope of the present invention.

Claims

1. A method for measuring fuel in a heterogeneous fuel tank, characterized in that, The upper ends of the heterogeneous fuel tanks are connected, and the heterogeneous fuel tanks are sequentially divided into several measurement units according to the unconnected parts at the lower ends of the heterogeneous fuel tanks; several fuel quantity sensors are sequentially connected from top to bottom in the measurement unit. The fuel quantity sensors are divided into three sections from top to bottom: upper unmeasurable, normal immersion, and lower unmeasurable. Each fuel quantity sensor is provided with a fuel mass characteristic database in which the fuel level corresponds to the fuel quantity; the corresponding fuel quantity is obtained according to the fuel level of the fuel quantity sensor in each measurement unit, and the fuel quantities of all measurement units are summed to obtain the fuel quantity of the heterogeneous fuel tank; In the measurement unit, among adjacent fuel quantity sensors, if the fuel level of the upper fuel quantity sensor is in the lower unmeasurable section and the fuel level of the lower fuel quantity sensor is in the upper unmeasurable or normal immersion section, then the fuel quantity corresponding to the measurement unit is queried from the fuel mass characteristic database based on the fuel level of the lower fuel quantity sensor; In the measurement unit, among adjacent fuel quantity sensors, if the fuel level of the upper fuel quantity sensor is in the upper unmeasurable or normal immersion section and the fuel level of the lower fuel quantity sensor is in the upper unmeasurable section, then the fuel quantity corresponding to the measurement unit is queried from the fuel mass characteristic database based on the fuel level of the upper fuel quantity sensor; In the measurement unit, among adjacent fuel quantity sensors, if the fuel level of the upper fuel quantity sensor is in the upper unmeasurable or normal immersion section and the fuel level of the lower fuel quantity sensor is in the normal immersion section or the lower unmeasurable section, then the measured fuel quantity of the upper fuel quantity sensor is queried from the fuel mass characteristic database based on the fuel level of the upper fuel quantity sensor, and the range of the lower fuel quantity sensor is subtracted to obtain the actual measured fuel quantity of the upper fuel quantity sensor. Then, the measured fuel quantity of the lower fuel quantity sensor is queried from the fuel mass characteristic database based on the fuel level of the lower fuel quantity sensor and added to obtain the fuel quantity corresponding to the measurement unit; In the measurement unit, among adjacent fuel quantity sensors, if the fuel level of the upper fuel quantity sensor is in the lower unmeasurable section and the fuel level of the lower fuel quantity sensor is in the lower unmeasurable section, then the fuel quantity is set to zero.

2. The fuel measurement method for a heterogeneous fuel tank according to claim 1, characterized in that The ranges of the upper unmeasurable and lower unmeasurable sections of the fuel quantity sensor are the error tolerance ranges of the fuel quantity sensor.

3. A method for measuring fuel in a heterogeneous fuel tank according to claim 1, characterized in that, The heterogeneous fuel tank is sequentially divided into several measurement units according to the number of inner closed bottom surfaces that are not connected at the lower end of the heterogeneous fuel tank.

Images