JPS6171321A - Fuel measuring device of flying body - Google Patents

Abstract

PURPOSE:To make it possible to measure fuel, by computing the amount of fuel by a process unit based on acceleration (g), density rho, liquid level H and internal pressure PT, and providing a small number of liquid level detectors having a simple constitution. CONSTITUTION:Acceleration (g) of a flying body, density rho of fuel, liquid level H of fuel, which is measured by liquid level detectors 13 of fuel constituted by a pressure transducer, and internal pressure PT in a fuel tank1, which is measured by an internal pressure detector 1l5, are inputted to a process unit 17. Then the amount of fuel in the fuel tank 1 is obtained. This measuring apparatus can measure the fuel by only providing a small number of liquid level detectors having a simple constitution. Therefore the weight can be reduced to a large extent in comparison with conventional technology. When three liquid level detectors are provided, a highly accurate fuel measuring system can be formed. Even if two of them fail owing to any reason, the fuel can be measured and high reliability is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a fuel measuring device for an aircraft, particularly for measuring the measured fuel level, fuel density, air pressure in a fuel tank, and aircraft fuel. The present invention relates to a fuel measuring device for an aircraft having a configuration in which a process unit calculates and determines the amount of fuel in a fuel tank from each measurement value of acceleration.

<Conventional technology> The conventional technology will be explained below with reference to the drawings.

FIG. 9 is a block diagram of a conventional fuel measuring device for an aircraft. In other words, the technology shown in Figure 9 uses the fact that the capacitance, which is the output of a capacitance type liquid level meter, is proportional to the immersion height of the fuel and the fuel electrostatic coefficient to measure the fuel in the fuel tank. It is a technology to measure

In Fig. 9, a fuel tank 1 is installed, for example, in the main wing of an airplane and stores fuel 2 (generally installed in the main wing, but there are also some installed in the fuselage, etc.), and the shape can also be one-piece or split. (In the case of an integrated type, the main wing tank is generally thin and has a horizontally long shape); Since it is necessary to measure the liquid level δ of the fuel 2, the capacitance type liquid level 81.4, which is set separately in each part, is a convencator unit installed to correct the fuel dielectric coefficient K of the fuel 2. , 5 is the density ρ of the fuel 2, and the density n1.6 is the process unit. This process unit 6 has a "liquid level (δ)-volume (V) characteristic" that matches the shape of the fuel tank 1.
0), a memory 7 in which information such as calculation methods is stored, a capacitance input interface 8 to which the liquid level meter 3 and convencator unit 4 are connected, and a frequency to which the density meter 5 is connected. The input interface 9 and the calculation function 11 input information and measured values in the memory 1 via the data bus 10 and perform calculations, and the calculation function 11 inputs values such as the total weight of the aircraft and the required refueling m. and an input/output interface 12 that outputs the calculation results.

The measurement and calculation operations when configured in this way will be explained below. The calculation function 11 first calculates the fuel electrostatic coefficient 1 minus the fuel liquid level δ1 at each position. δ2. The capacitance IQ++Q2+~Qn is the output of the liquid level al'3 proportional to ~δn.
Input this capacitance Q++Q2. The influence on the fuel electrostatic coefficient included in ~Qn is corrected using the measured value of the compensator unit 4, and the fuel level δ11. δ21. ~δn
Find +.

Next, the respective volumes V of the corrected liquid levels δI++ 621+ to δn1 are converted using the δ-■ characteristic matched to the shape of the fuel tank. Next, the three liquid level ■1
3 to find the liquid level inclination angle, and use this liquid level inclination angle to correct the liquid level inclination for the volume V obtained by the δ-■ characteristic. Finally, the volume (2) corrected for the liquid level slope is multiplied by the density ρ to determine the weight remaining amount W of the fuel.

Problems that cannot be solved by this invention> Such a fuel measuring device for an aircraft requires a large number of liquid levels a1, and requires a large number of wires because each one is routed independently. do. In addition, since the liquid level meter is a capacitance type, it is necessary to use a coaxial cable or a shielded wire for this line, and the wiring cannot be exposed to strong IR (if the fuel tank is located on the main wing, the distance will increase due to the distance). r7Bff).

■If you properly characterize the shape of the fuel tank and output the output of the liquid level meter in parallel, one of the
If one of the wires breaks, the failure cannot be detected and an error occurs.

■Capacitance-type liquid level gauges are weak to one inch and have poor maintainability.

There are other problems.

<Object of the Invention> The present invention has been made in view of the above-mentioned problems, and the present invention is based on the acceleration of the aircraft, the lightning speed of the fuel, and the air pressure and fuel in the fuel tank measured using a pressure quadrangle shaker. It is an object of the present invention to provide a fuel measuring device for an aircraft, which has a simple and inexpensive configuration, is resistant to shocks, is capable of fault isolation, and is easy to use for multi-flux output wiring.

Means for Solving the Problems> To achieve the above-mentioned object, the fuel measuring device for an aircraft of the present invention measures the amount of fuel in a fuel tank provided in an aircraft. The density ρ of the fuel is measured with an accelerometer, and the fuel liquid level (hereinafter referred to as "immersion height") is measured using an accelerometer. H and the internal pressure Pt in the fuel tank are measured by a liquid level detector and an internal pressure detector composed of a pressure transducer, and these acceleration UG, density ρ, and liquid level are measured. H and internal pressure F'
The system was configured to calculate the amount of fuel using a pro-his unit based on T.

During flight, the value of pressure PF obtained from the liquid level detector consisting of a pressure fluid transducer is calculated by multiplying the density ρ by the product of the immersion height 9 and the immersion height PT by the internal pressure PT. is added. Therefore, in order to obtain this immersion aiH, in addition to the pressure PF which is the output of the pressure sensor
, the acceleration q from "Immersion height) - I J -, which is preset in the process unit using each measured value,
The amount of fuel in the fuel tank is calculated using the characteristics such as "r volume V".

<Example> Hereinafter, the present invention will be described in detail using drawings which are specific examples. In addition, in the following drawings, figures 9 to 10
Portions that overlap with those in the figures are given the same numbers and their explanations will be omitted.

FIG. 1 is a block diagram showing a specific embodiment of the fuel measuring device for an aircraft according to the present invention.

In FIG. 1, reference numeral 13 denotes a liquid level detector composed of a pressure fluid transducer that measures the immersion height H of the fuel 2 as pressure PF. In FIG. 1, three pressure transducers 13a to 13c are spaced apart! .

Since the aircraft tilts not only from side to side but also from front to back, we installed at least 3 (more than 3 can be installed to improve safety) pressure fluid transducers to adjust the liquid level inclination angles θ and φ. This is to find out.

Reference numeral 15 indicates an internal pressure detector which is set in a position not in contact with the fuel 2 in the fuel tank 1 and has a pressure transducer for measuring the air pressure within the fuel tank 1. Reference numeral 16 indicates an internal pressure detector which measures the acceleration of the flying object. This accelerometer 16 may be installed in the processor unit described below, or may be installed separately in another location.17 is a liquid level detector 13 and a density meter 5. This is a pro-his unit to which an internal pressure detector 15 and an accelerometer 16 are connected, and which calculates the amount of fuel in the fuel tank 1 from each measurement 11t1. A frequency input interface to which a menu 18 in which immersion height (+-1)-volume (V) characteristics, calculation methods, etc. are stored, a liquid level detector 13, a density meter 5, and an internal pressure detector 15 are connected. 19 (many pressure cadence reducers Yadodo 51 have frequency output types, so here we use a frequency input interface) and acceleration 511G.
an acceleration signal interface 20 to which is connected, and an input/output interface 23 that manually inputs this information and, for example, information on the required amount of refueling and outputs the calculation results.
and an arithmetic function 22 that inputs information from the computer via a data bus 21 and performs arithmetic operations.

Below, the functions and operations of the fuel measuring device for an aircraft having the configuration shown in FIG. 1 will be analyzed and explained in detail.

(1) Figure 2 is a diagram showing the concept of immersion height for different shapes of fuel tanks, and Figures 2 (A) and (B)
) shows a rectangular parallelepiped fuel tank, and FIG. 2(C) shows an integral structure fuel tank housed within the main wing.

(ii): Figures 3 and 4 are diagrams showing the characteristics of the liquid level detector with respect to the shape of the fuel tank.

FIG. 3(A) shows the shape of a fuel tank when the volume change with respect to high immersion force is linearly proportional. In Figure 3 (A>), the immersion height η is as follows: η= (PF-P□)/ρ・q...(1
). As shown in Figure 3 (B), the η-V characteristic of the fuel tank is a straight line with the bottom area S as a proportionality constant, so the volume V is: υ=η・S= (PF PT )S/ρ・9 ...
(2) becomes. Therefore, the remaining weight W of fuel is W-ρ・υ-(S/Q)・(PF-PT)...(
3). If the acceleration q and the internal pressure Pt are constant, then
W=KI]p...(4
), and the flu suspension W can be expressed as q. By the way, since the fuel tank of a boat is generally not a rectangular parallelepiped, such a calculation method cannot be used.

(itl): Figure 4 (A> is the shape when the volume change is ?9 1, such as the fuel tank of an aircraft. In this case, the immersion height 1-1 is H = (PF - 1Py) /ρ・9...
・It becomes (5). The volume V is a function of the immersion height H (V=I(1
-1)), the H-V characteristic of the fuel tank is, for example, as shown in FIG. 4(B). The volume V is determined from this H-V characteristic, and the remaining amount W of heavy oil in the fuel can be calculated from the product of the density ρ and the volume V. In this way, it is possible to easily measure the liquid level by simply installing a liquid level detector constituted by a pressure transducer at one location at a position where fuel is constantly immersed in iQ.

(■): Next, we will explain the concept of liquid level slope.

distance! If you set two pressure cadence juicers at an interval of , it is possible to measure the liquid level at each position.
If the liquid level is inclined, the degree of inclination can be detected. FIGS. 5 to 7 are diagrams for explaining this. Incidentally, when explaining FIGS. 5 to 7, the internal pressure Pp is treated as O in order to simplify the explanation of A.

FIG. 5(A) shows a case where there is no liquid level inclination, and FIG. 5(B) shows a case where a liquid level inclination (the inclination angle is φ) occurs when the blade is deflected or in a rising position.

In FIG. 5, the detected pressure of the liquid level detector 13a is Ppa (tQ immersion height is ha), and the liquid level detector 1
3t) is Ppb (the immersion height is hb), and the distance between the liquid level detectors 13a and 13b is l, then the detected pressures Ppa and Ppb are PFa-ρ・9・h
a Pt-b = ρ・9・hb...
(6) becomes. Therefore, the inclination angle φ is φ=s i n' ((hb − ha ) /1)=
s in” ((Pp b - Pp a )/ρ・
9.! )...(7) becomes. Therefore, if the shape of the fuel tank is determined, the volume V can be uniquely determined by determining the immersion angle φ and the inclination angle φ. This corresponds to h-v characteristics.

By characterizing the fuel as a φ-V characteristic, an arbitrary fuel volume V can be determined, and an output fuel amount W can be determined from W=ρ·V.

In addition, [), φ-■ characteristic is a curve characterized in order to determine the fuel volume ■ from the immersion height and inclination angle φ from a certain determined bottom surface of a specific fuel tank (13). It varies depending on the shape of the fuel tank. In Figure 1,
Further, θ is obtained by adding the inclination angle θ in the longitudinal direction to the φ-V characteristic.

Although the h and φ-■ characteristics are necessary, the inclination angle θ is omitted here to simplify the explanation.

FIGS. 6(Δ) and (B) are explanatory diagrams for determining the small h) remaining amount when the aircraft makes a coordinate turn.

In FIG. 6, when a lateral acceleration Ny is applied during a coordinate turn, the acceleration G applied to the fuel tank becomes an amount combined with the gravitational acceleration 9. Therefore, the liquid level detector 13a
, 13b detected pressure Ppa, PFb is Ppa-ρ・+y-ha-(8)PF
b = ρ・ +Ny2 > ・hb
... (9). Therefore, the immersion height is (
From formula 6), ha=Ppa/ρ・+N y −(
10). The inclination angle φ is φ−5in'((
hb ha>/i'), so hb=ha, so φ=
It becomes O. By finding the fuel volume V from the h, φ-■ characteristics and multiplying it by the density ρ, the weight extra weight ff1W of the fuel can be found.

FIGS. 7(A) and 7(B) are explanatory diagrams for determining the heavy lifting residual amount of fuel when sideslip due to lateral acceleration or forward acceleration is applied.

In FIG. 7, when the fuel tank is horizontally installed or when forward acceleration is applied due to lateral acceleration Ny, the fuel tank is horizontal but the liquid level is inclined.

Liquid level detector 13a in this case.

The detected pressures PEa and Ppb of 13b are as shown in equations (8) and (9), and the immersion height is as shown in equation (10),
The inclination angle φ is φ-5i n' ((hb-ha ＞/1)=s i
n” ((PF b −1] p a )/ρ ・
・
l) ... (11). If the shape of the fuel tank is determined, then calculate the fuel volume V from the φ-■ characteristic in the same way as described above, and multiply it by the density ρ to find the weight of the fuel, ff1.
Find W.

(V): Based on FIGS. 5 to 7, the method for detecting the remaining amount of fuel will be explained using the diagram of the fuel tank in the main wing in FIG. 8.

When a pressure fluid transducer is used as a liquid level detector, if the gravity at one point of a fluid at rest in a closed container is increased by a certain amount, all points in the fluid will be According to Pascal's principle that the pressure of increases by the same amount, the liquid level detector 13a detects that when the liquid level is at α, β, μ,
For Hα, 1β, and H21, respectively (II corresponds to ρ・9・1−
1 is detected. Hence the spacing! If the liquid level detector 13b is installed at the position, the immersion height 1'' and the liquid level inclination angle φ can be detected no matter where the liquid level is. Furthermore, a liquid level detector 13c detects the inclination angle θ in the front-rear direction.
If these are installed at intervals on the liquid level detector 13a as shown in FIG. 1, for example, the remaining fuel amount W can be detected with higher accuracy.

By the way, with such a configuration, even if the two liquid level detectors fail for some reason, the remaining fuel amount W can be measured as described above.

<Effects of the Invention> As described above, the present invention has been described in detail along with specific examples. Fuel density ρ and pressure ・Fuel liquid level 1 to 1 and internal pressure PT in the fuel tank measured by a liquid level detector composed of a transducer and an internal pressure detector
The fuel measuring device for an aircraft according to the present invention, which is configured to calculate the amount of fuel in a fuel tank by inputting it into a process unit, can measure the amount of fuel by simply setting a small number of liquid level detectors with a simple configuration. can be measured, so the weight can be significantly reduced compared to conventional technology. In addition, a highly accurate fuel measurement system can be constructed by setting up three liquid level detectors, but it is highly reliable in that even if two of them fail for some reason, fuel measurement is still possible. It becomes a device. Furthermore, the liquid level detector composed of a pressure displacement sensor is resistant to movement and is superior in maintainability such as inspection and maintenance. There are other effects.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a specific embodiment of the fuel measuring device for an aircraft according to the present invention, Fig. 2' is a diagram showing the concept of immersion height for different shapes of fuel tanks, and Fig. 3. and Fig. 4 are diagrams showing the characteristics of the liquid level detector mounted in the shape of a fuel tank, and Figs. 5 to 7 show that -C liquid level inclination can be detected using pressure transistors installed at two locations. Figure 8 is a diagram explaining the method of detecting the remaining amount of fuel assuming a fuel tank inside the main wing. Figure 9 is a block diagram of a conventional fuel measuring device for an aircraft. Figure 10 is a δ-■ characteristic diagram. 1...Fuel tank, 2...Fuel, 3...Capacitance old type liquid level gauge, 4...Convencator unit,
5... Density '1, 6, 1γ... Process unit,
13... Liquid level detector, 15... Internal pressure detector,
1G...accelerometer.

Claims (1)

[Scope of Claims] A fuel measuring device for an aircraft that measures the amount of fuel in a fuel tank provided in an aircraft, comprising: (1) a liquid level configured to measure the liquid level of the fuel using a pressure transducer; (2): a density meter for measuring the density of the fuel; (3):
an internal pressure detector that is configured to be in contact with the fuel and that measures the air pressure in the fuel tank using a pressure transducer; (4) an accelerometer that measures the acceleration of the flying object;
5): A process unit to which the liquid level detector, the density sensor, the internal pressure detector, and the accelerometer are connected, and calculates the amount of fuel in the fuel tank from the measured values of each of these. A fuel measuring device for an aircraft, characterized by comprising: