JPS6198698A - Measuring device for fuel of missile - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field 2> The present invention provides a tank unit (hereinafter abbreviated as r T / U j) that outputs the liquid level of fuel as a capacitance, and a tank unit that outputs the liquid level of fuel as a capacitance, and A configuration that calculates and calculates the weight of an aircraft's fuel per unit based on a compensator unit (hereinafter abbreviated as rC/UJ) that outputs capacitance and a density meter that measures density. This invention relates to a fuel measuring device for an aircraft.

<Conventional technology 2. Previously known fuel measuring devices for aircraft of this type: ■
: "Aviation Instruments" of Jijin Shokan (published October 5, 1978), and ■: Yokogawa Technical Report (published by Yokogawa Hokushin Electric Co., Ltd. in 1988) Vo 1.28 No.

2, page 179.

The technology described in these documents is based on the capacitance type liquid level i
The fuel in the fuel tank 1'31 is measured by utilizing the fact that the output of the fuel tank 1'31 is proportional to the fuel level and the fuel λ'31 electrostatic coefficient.

FIG. 2 (△) is a diagram showing the basic principle of a capacitor.

In Fig. 2 (A>), 1 is a fuel tank that stores the fuel 2 of the aircraft, and 2a is a liquid level electrode that takes out the capacitance CT from the liquid level χ of the fuel 2. At this time, the capacitance CT is , CT=CD(1+χ(K-1>)...(1)
bawl. However, CD is the capacitance when the fuel tank 1 is completely filled with air (hereinafter referred to as "dryer A tube"), 1 is the dielectric coefficient of the fuel 2 (the electrical coefficient of the fuel tank 12 (approximately 2) is the air (
1)).

Fig. 2 (B) #; be.

In FIG. 2(B), 3 is a capacitance type liquid level sensor T7'U which is a more specific version of the liquid level electrode 2a. This T/U3 is a coaxial double cylindrical electrode (h
1 will be completed. At this time, the dry cap Co is Co = 24.1 K (!/ 1ag 10(a /b) CI)F/m
Ko (2) Yell. however,! is the length of the cylinder. Normally, a dry 4-near CD is several tens of pF. [ is the AC power supply, 1 is the transformer, 4 is the amount of current, 50 is the capacity ffi CF
It is a balancing capacitor with Here, the voltage at one end of the transformer T connected to T/U3 is V2, the voltage at one end of the transformer T connected to the balancing capacitor 43-50 is V2, and the voltage flows from T/'U3 to the connection point 0. current rTs
The current flowing from the connection point O to the balancing capacitor 50 is expressed as IF
% The current flowing from the connection point O to the current amount 4 is assumed to be 11. At this time, the current Ih is In-Jy-IF -θ V+ CT -ω V2CF
... (3). To this (1
), the current TM becomes Ih −ωV+ Co
+(t)V,')C(K-1)C.

-ωV2 CF...(4) It becomes. However, ω is the angular velocity. In equation (4),
Assuming that it is adjusted so that V+Co =V2Ct:, the current IM becomes In-ωV1χ(K-1)Co (5). Therefore, when the fuel 2 is empty, it is χ-0, and when the fuel '1 is full, it is χ-1, and at this time, the ammeter 4 shows Ih.
A current of =0 to ωV+(K-1)Go flows. By reading this amount of current from the indication on the ammeter 4, the level of the fuel 2 can be determined.

FIG. 2(C) is a block diagram illustrating a highly accurate servo type force control instruction system which is a further embodiment of FIG. 2(B).

In FIG. 2(C), 5 is a servo amplifier, 6 is a servo motor, 7 is an indicator (indicated value is M), 8 is a bodentiometer, and 60 is a balancing capacitor having a capacitance Cs. Here, 1, the current flowing on each side of the bridge is Il
, r2. r3. If Io, the current is 1+, 12. J3.
JolJ, − respectively, Il (−ω\/1(C□+
χ(K-1)Co)).

12 (-(1)V20F), 13 <-M(t)
V3Ca).

Roaring. Here, the equilibrium condition of the bridge is ■ 〇
-T 1 -T 2 +I 3 =O...
・Since (6) is satisfied, substituting the values of each current mentioned above gives the formula (6): tJg V +Co +
χ (K 1 ) V+C.

+V2CF +MV3 CB =O-(7). Therefore, the instruction value M of the instruction 817 is M−[VICD→−χ
(K-1) VICD 10 V2 Cr-) / V3 C
s...(8). Now, when the fuel is empty, χ
-0. Since M-0, equation (7) is: V+ Go = V2 CF
...(9). On the other hand, when the fuel is full, χ-1. Since M-1, the formula (7) is V+ Co 4- (K 1 ) V+ C.

10V2 CF 10V3 CB =0,', KV+ Co +V2 CF =-V3 CB
−(10). These equations (9) and (10) can be expressed as
Substituting into the equation, it becomes M−χ (11). ■+ so as to satisfy equations (9) and (10),
By setting one shift for V2, Co, CF, and CB (P'), fuel can be measured and given instructions using the bridge circuit shown in FIG. 2(C).

By the way, if fuel instructions are required in units of weight (for example, gas turbine aircraft), it is necessary to convert volume to weight. That is, since T/U3 is the liquid level sensor 1, its output is a function of the volume of the fuel, and in order to find the weight, it is necessary to multiply it by the fuel density ρ. Therefore, by taking advantage of the fact that the fuel density ρ is a function of the dielectric constant 1, we set up a dielectric sensor C/U9 for the fuel 2, shown by a broken line, in parallel with the balancing capacitor 60, and determined the characteristics of the circuit. is consistent with the density-permittivity correlation equation 4 (%(1)) (However, TA and TB are specific values determined by the airplane manufacturer or values determined by MILL, etc.) By writing the following, it is possible to quickly obtain the indicated value M proportional to the fuel.

・Problems to be Solved by the Invention> By the way, the above-mentioned fuel density-permittivity correlation equation 1 is a statistical) open equation, and actually varies depending on the fuel.

As a result, there is a problem in which an error of about 4% at maximum occurs.

(Object of the invention) 1! This was done in view of the problem of
The purpose of this research is to provide a high-precision arithmetic circuit for measuring the combustion of an aircraft.

<Configuration m for solving the problem: The fuel measuring device for an aircraft according to the present invention for achieving the above-mentioned object has the following configuration.

Density is a constant current (DC) based on the measured fuel density.
output the density signal. This density signal is T/U and C
/IJ is output to the fuel density calculation section, which is a circuit that outputs a value proportional to the density and is composed of a density detection circuit and a calculation circuit connected to the connection point of IJ.

The fuel density calculation unit inputs the density signal and outputs a voltage proportional to the density to the input terminal of the fuel remaining amount calculation unit. That is, the density signal is converted into a DC voltage by the density detection circuit, and the AC voltage from the constant voltage part is input to one side of the multiplier, which becomes the other input value of the multiplier, and the multiplier multiplies these voltages to change the amplitude to the density. Output as a proportional AC voltage signal. The capacitance type T/U used as a liquid level sensor for measuring the fuel liquid level is excited by the AC voltage signal from the fuel density calculating section and outputs a capacitance value corresponding to the liquid level. do. C/U, which is a dielectric constant sensor that measures the dielectric constant, has one end connected in series to this T/U and the other end connected to the output terminal of the remaining fuel amount calculating section.
It outputs a capacitance (■) corresponding to the dielectric constant (T, , /
The connection point between U and C/U is connected to the feedback terminal). On the other hand, in the internal circuit of the remaining fuel amount calculating section, a dry cap canceling circuit for canceling the T/U dry cap is provided between the input terminal and the feedback terminal, and an oil cylinder amplifier and a dry cap canceling circuit are provided between the feedback terminal and the output terminal. The structure includes a dielectric coefficient cancellation circuit that cancels out the influence of the dielectric coefficient of l. Therefore, the remaining fuel amount calculating section can eliminate the dielectric 1 system fault and the dry cap, and obtain an output value proportional to the remaining fuel amount. That is, this output value is T, -'
U is the part immersed in the flame 1, and is also proportional to the excitation voltage of T//U. As a result, the output value is proportional to fuel volume x density, that is, fuel weight. This output value cannot be displayed on the display unit.

Embodiments Hereinafter, the present invention will be explained in detail with reference to FIG. 1, a block diagram showing a specific embodiment of the burn-up measuring device for an aircraft according to the present invention. In addition, in FIG. 1, parts that overlap with those in FIG. 2 are designated by the same number f=t, and the explanation thereof will be omitted.

In FIG. 1, T/U 3 is defined as
It is excited by the output from the fuel density calculation section, which is a circuit that outputs one cycle proportional to the density, and outputs the capacitance corresponding to the liquid level χ of the fuel 2 as the output current 1a.
Reference numeral 9 inputs the output value from the remaining fuel amount calculating section described below, and outputs the capacitance corresponding to the dielectric constant 1 of the fuel 2 as the output current Ic. This T/U 3 and C/U 9 are connected at a connection point α. 1o is a density meter that measures the density ρ of fuel in the fuel tank 1 installed in the aircraft and outputs a DC current density signal 1o that is proportional to the density of the fuel.

This density meter 10 is connected to a connection point α. Reference numeral 11 denotes a fuel density calculation unit connected to the connection point α. This fuel density calculation unit 11 inputs the density signal Io from the density meter 10 via the connection point α, and receives, for example, an AC voltage signal VD−VTef whose amplitude is a value proportional to the density ρ (where Vo=n+ρ, nl is a constant). The 1M structure of the fuel density calculation unit 11 includes a density detection circuit 12 which inputs a density signal To and outputs a DC voltage signal Vo proportional to the density ρ, and a density detection circuit 12 that inputs a density signal To and outputs a DC voltage signal Vo proportional to the density ρ. It is comprised of an arithmetic circuit 13 and f's+ that calculate and output an AC voltage signal VD-Vaer proportional to the density ρ. Here, the density detection circuit 12 includes a resistor 12b having a resistance value R2.
For example, operational amplifier Q4 with low-pass filter characteristics
A feedback resistor 12a having a resistance value R7 is connected in parallel to the series circuit. Now, if a current of 1 flows through the feedback resistor 12a of the density detection circuit 12, the operational amplifier Q2 in the remaining fuel amount calculation section described below
A DC voltage -iR is output, and the operational amplifier Q4 of the density detection circuit 12 detects the DC component of the output voltage of the operational amplifier Q2, and generates a DC voltage (Vo) that cancels this (this DC voltage The voltage (Vo) is fed back to operational amplifier Q2 through resistor 12b). As a result, the operational amplifier Q
The DC component appearing in the output of 2 becomes zero, and the density is 511
All of the current Io of 0 or 1 flows into the density detection circuit 12. That is, Vo −−R2・Io ” (fuel density') −(1
2), and the DC voltage (Vo) of the density detection circuit 12 is
is proportional to the fuel density (note that when transmitting the density signal, the fuel leak resistance is parallel to the feedback resistance R1, but the resistance R
A change of 1 does not affect the operation of operational amplifier Q4, so it does not result in an error). The arithmetic circuit 13 also includes a constant voltage section 14 and a multiplication section 15 that multiplies the AC voltage (Vrer) from the constant voltage section 14 by the DC voltage signal VD from the density detection circuit 12.

16 is an input terminal 16a for the AC voltage signal VD-V7ef.
Input the combined current of T/U3 and C/U9 from the feedback terminal IGb connected to the connection point α, eliminate the dielectric coefficient K and the dry cap, and obtain the output value Vo proportional to the remaining fuel amount. This is a remaining fuel amount calculation unit that outputs from the output terminal 16c. This remaining fuel amount calculating section 16 is configured as follows. A dry cap canceling circuit 17 is arranged between the input terminal 16a and the operational amplifier Q2, and is configured of an amplifier Q with a gain of (-1) and a capacitor 17a with a capacity of 111cTD, and cancels the dry cap of the T/U3. The output current of the dry cap cancellation circuit 17 is assumed to be Ib. The connection point between the dry cap circuit 17 and the input terminal of the operational amplifier Q2 is connected to the feedback terminal 16b. The output terminal of operational amplifier Q2 is connected to output terminal 16G. Furthermore, the output Vo of the operational amplifier Q2 is connected to the input terminal of the operational amplifier Q2, and the output Vo of the operational amplifier Q2 is connected to the amplifier Q3 with the gain (-1) and the capacitor ff.
Fuel dielectric @1 consisting of a capacitor 18a of 1cco
A feedback current 1d is fed back via a dielectric coefficient cancellation circuit 18 that cancels the influence of <. This fuel remaining m calculating section 1G will be explained in more detail.

If the dry cap is CTO, the D capacitance fitlcvu of T/U3 is calculated from equation (1) as follows: 'CT low -CTO[1+χ (K-1>1
... (13) On the other hand, the capacitance C of C/U9
If co is dry 4, let Cco be Ccu = -Cco ・= (14). On the other hand, each current Ia to ■d is calculated as follows, where S is the operator, Ia = SCruun+ρVrer -SCTo(1+χ(K-1)) -Il, ρVrer = (15)Ib -
−SCT D −n+ ρVre f −(16
) IC-8CCU -vo -8KCco ・Vo -(1
7) Id=-8Cco-Vo-
<18). Therefore, the equilibrium condition of the bridge is Ia
-1-rb+Ic+Id=O-(19), so (
18) The formula is 5CTo(1+χ(K 1))・nl, QVr
e r -8CT o 011+ ρV1-er+5K
Cco-Vo-8COD-V. ...(20). Therefore, the output value Vo of the fuel oil '31 residual calculating section 1G is:
Vo --[((CT o1χ(K-1)-Cto)
CT[))/(KCco Cco)co-71, ρVrer-(21). Here, CTO=Cto z Cco=Cc.

If we choose CT o % Cco so that (19)
Formula % Formula %), and the output voltage Vo is (1 volume of combustion) x (density) -
It becomes 1 shift, which is 1 row compared to (1,000 square feet).

Note that the dry cap cancellation circuit and dielectric coefficient cancellation circuit of FIG. 1 of the present invention are not limited to the circuits described herein. For example, an amplifier Q that adjusts the gain of (-1) to the right
+, if Q3 is made to have a gain of (-N), the capacitors 4j17a, 11'! The body of a (CT
o /N) and (Cco /N), no difference in equivalent characteristics will occur.

Here, the output value V. can be displayed on a display unit 19, which is composed of, for example, a digital-to-analog conversion circuit and a display, as shown by broken lines.

,'Effect of the invention.

The present invention has been described above in detail along with specific examples.Thus, the present invention has been described in detail with reference to a densitometer that measures the density of fuel PI, and a fuel density meter that outputs a value proportional to the density based on the density value j. The calculation section and the fuel 2' excited by the output from the fuel density calculation section
! T/'U that measures the liquid level of 1, C/U that measures the dielectric constant of fuel, and fuel density calculation section T,/U and C.
, / U and density meter are connected to check the remaining fuel (fuel 2
The fuel measuring device for an aircraft according to the present invention, which is composed of a fuel remaining amount calculation unit that outputs a value proportional to The true fuel weight can be obtained without the maximum error of about 4% that occurs when using the standard "fuel density-permittivity correlation equation," providing an extremely effective technology for measuring fuel for aircraft. can do. In addition, by using a density detection circuit that uses a DC balance method as a circuit that converts the density signal, which is a current value, into a voltage, the density signal (DC
) and the remaining fuel amount signal (AC>) can be transmitted on the same line.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a specific embodiment of the fuel measuring device for an aircraft according to the present invention, and FIG. 2 is a diagram showing the prior art. Figure 2 (B) is a diagram showing the type of the basic principle of the capacitor shown in Figure 2 (A). Fig. 2 (C) is a block diagram showing an instruction system consisting of a high-precision servo system that further embodies the structure shown in Fig. 2 (13). il tank, 2...fuel, 3...tank unit 1-(T/U), ri...to compensator unit 1 (C/U), 10...density th1i...fuel density calculation unit, 1C...Fuel remaining amount calculation section.

Claims (1)

[Scope of Claims] A tank unit that outputs the liquid level of fuel in a fuel tank provided in an aircraft as a capacitance, and a compensator unit that outputs the dielectric constant of the fuel as a capacitance. In a fuel measuring device for an aircraft, A: one end is connected to a circuit that outputs a value proportional to density, and the other end is connected to one end of the compensator unit (e.g. 9) and a density meter (e.g. 10); B: the tank unit (for example, 3) connected to the connection point of the compensator unit and the tank unit; A fuel density calculation section (for example, 11) which is a circuit that outputs a value proportional to the density; C: The fuel calculation section is connected to the input terminal, the other end of the compensator unit is connected to the output terminal, and the feedback terminal A dry cap cancellation circuit (for example, 17) is connected to the connection point portions of the tank unit, the compensator unit, and the density meter, and is connected between the input terminal and the feedback terminal to cancel the dry cap of the tank unit. and an amplifier (for example, Q_2) and a dielectric coefficient cancellation circuit (for example, 18) for canceling the influence of the dielectric coefficient of the fuel, and a value proportional to the remaining amount of fuel in the fuel tank (for example, 1) is provided between A remaining fuel amount calculation unit (for example, 16) that calculates and outputs
A fuel measuring device for an aircraft, comprising: