System for measuring oil quantity of oil tank

Abstract

The invention discloses an oil tank oil quantity measuring system which comprises a measuring capacitor, the measuring capacitor comprises measuring subunits arranged in all oil tank compartments, each measuring subunit comprises a P-pole capacitance thin film and an N-pole capacitance thin film, and the P-pole capacitance thin films and the N-pole capacitance thin films are oppositely arranged on the two side walls in the compartments respectively; the P-pole capacitance thin film and the N-pole capacitance thin film can sense the contact with fuel oil, so that the capacitance value of the measurement subunit can change along with the change of the fuel oil coverage area; and measuring the oil quantity of the oil tank according to the capacitance value of the measuring capacitor. By adopting a mode of sensing the change of the fuel oil coverage area by the capacitance film and measuring the volume of the fuel oil in the oil tank, based on the characteristics that the area of the capacitance film covered by the fuel oil with the same volume is unchanged and the coverage area of the capacitance film is linearly related to the output capacitance value under different flight attitudes, the measurement system needs few parts, and the measurement accuracy is high. The structure is simple and reliability is high.

Description

Technical Field

[0001] The invention belongs to the field of measurement technology, and in particular relates to a fuel tank oil quantity measurement system. Background Art

[0002] In order to improve the carrying capacity of modern large transport aircraft, fuel tanks are generally distributed in the wings with relatively flat structures, and the liquid level is distributed widely. Figure 1 As shown, a traditional distributed fuel level measurement system employs a number of concentric tube capacitive fuel level sensors placed in each compartment of a fuel tank. These sensors are used to sense the liquid level at specific locations. Based on the current tank posture, the remaining fuel volume in each tank is determined by querying a corresponding height-angle-volume mapping table. Due to the relatively flat nature of fuel tanks and the presence of sealing ribs and semi-sealing ribs, a large number of concentric tube capacitive fuel level sensors are often required. Some large transport aircraft have over 60 sensors. This large number of sensors requires more interconnecting cables, significantly increasing the weight and complexity of the overall measurement system, and compromising the cost-effectiveness and reliability of the measurement system.

[0003] The distributed fuel quantity measurement system uses a fuel level sensor at a characteristic position to sense the liquid level to measure the fuel quantity. When the aircraft maneuvers and the fuel tank attitude is too large, the measurement system will have an unmeasurable dead zone, such as Figure 2 As shown, this may lead to discontinuous measurements or measurement deviations, which may provide erroneous indications to the flight crew. Summary of the Invention

[0004] The object of the present invention is to provide a fuel tank oil quantity measurement system to solve the problems existing in the existing distributed fuel quantity measurement system.

[0005] The present invention is achieved through the following technical solutions:

[0006] The fuel tank oil level measurement system includes a measuring capacitor, wherein the measuring capacitor includes a P-pole capacitor film and an N-pole capacitor film, and the P-pole capacitor film and the N-pole capacitor film are respectively arranged on the side walls of the fuel tank opposite to each other;

[0007] The P-pole capacitor film and the N-pole capacitor film can sense contact with the fuel, so that the capacitance value of the measuring capacitor can change with the change of the fuel coverage area;

[0008] The oil amount in the tank is measured according to the capacitance value of the measuring capacitor.

[0009] In some embodiments, the measuring capacitor includes a measuring subunit arranged in each fuel tank compartment, and the measuring subunit includes a P-pole capacitor film and an N-pole capacitor film, and the P-pole capacitor film and the N-pole capacitor film are respectively arranged on the two side walls of the compartment relative to each other.

[0010] In some embodiments, the P-pole capacitor film and the N-pole capacitor film each include a metal film layer and insulating film layers disposed on both sides of the metal film layer.

[0011] In some embodiments, the P-pole capacitor film and the N-pole capacitor film are adhered to the entire surface of the side wall of the compartment.

[0012] In some embodiments, the theoretical capacitance value of the measuring capacitor and the fuel coverage area satisfy the following relationship:

[0013]

[0014] Where ε1 represents the dielectric constant of fuel, ε0 represents the dielectric constant of air, K is the electrostatic force constant, d is the distance between adjacent P-pole capacitor films and N-pole capacitor films in the fuel tank or fuel tank compartment, S 总 is the total area of all P-pole capacitor films and N-pole capacitor films, S1 is the area of P-pole capacitor films and N-pole capacitor films covered by fuel, and N is the number of capacitors composed of one P-pole capacitor film and one N-pole capacitor film.

[0015] In some embodiments, a signal processing unit is further included, which is electrically connected to the P-pole capacitor film and the N-pole capacitor film, and is used to obtain the capacitance value of the measuring capacitor and calculate the oil amount in the tank based on the capacitance value.

[0016] In some embodiments, the P-pole capacitor film and the N-pole capacitor film of each measuring sub-unit are respectively connected to the signal processing unit through shielded wires.

[0017] In some embodiments, the signal processing unit includes an excitation module, a signal processing module, and a data processing module;

[0018] The excitation module is electrically connected to the P-pole capacitor film and is used to output an AC excitation signal to the P-pole capacitor film;

[0019] The signal processing module is electrically connected to the N-pole capacitor film and is used to collect the output current signal and process the current signal;

[0020] The data processing module is electrically connected to the signal processing module, and is used to calculate the capacitance value of the measuring capacitor according to the processed current signal and calculate the oil amount in the fuel tank according to the capacitance value.

[0021] In some embodiments, a CV tank characteristic database is further included, wherein the CV tank characteristic database includes mapping relationship data between capacitance values and tank fuel levels;

[0022] The data processing module calculates the fuel volume in the fuel tank according to the CV fuel tank characteristic database and the capacitance value.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] The present invention uses a capacitor film to sense changes in the fuel coverage area to measure the volume of fuel in the tank. Based on the characteristics that the area of the capacitor film covered by the same volume of fuel remains unchanged under different flight attitudes and that the coverage area of the capacitor film is linearly related to the output capacitance value, it can achieve accurate measurement of the fuel amount in the aircraft wing tank. The measurement system requires few components, has a simple structure, and is highly reliable.

[0025] Based on the fact that the theoretical capacitance of the measurement capacitor is linearly related to the fuel coverage area and that the fuel coverage area does not change with attitude changes, it is possible to measure the fuel amount in the fuel tank under any flight attitude, making the measurement system more applicable and universal.

[0026] Since the measurement system is not affected by the flight attitude, there is no need to obtain flight attitude data during measurement. Less data needs to be processed, the oil measurement algorithm is simpler, and the reliability and accuracy of the measurement data are higher.

[0027] This measurement system, which uses capacitive film as the sensing element, is lightweight and can be directly adhered to the side wall of the fuel tank when in use. It does not require any other mechanical connection structure and is easy to install and connect, thus reducing aircraft maintenance costs and aircraft failure rates.

[0028] Using a capacitive film as the measuring element, damage to the measuring element under impact from drops and collisions will not pose a risk of penetrating the fuel tank, nor will it damage the fuel supply pipeline. This meets the CCAR-25 standard for fuel tank explosion-proof protection under aircraft crash conditions and provides a high level of intrinsic safety.

[0029] The measuring system's measuring capacitor is excited by an AC signal with an excitation current in the microampere range. The steady-state energy introduced into the tank is in the nanojoule range, meeting the fuel tank safety protection airworthiness regulations of AC 25.981. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings in the embodiments will be briefly introduced below. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 Schematic diagram of the measurement principle of the traditional distributed oil quantity measurement system.

[0032] Figure 2 Schematic diagram of the measurement dead zone in traditional distributed oil measurement systems.

[0033] Figure 3 This is a schematic diagram of the arrangement structure of the measuring capacitor in the fuel tank in the fuel tank oil level measurement system according to an embodiment of the present invention.

[0034] Figure 4 The figure is a schematic diagram of the arrangement structure of the fuel tank fuel quantity measurement system in the aircraft wing fuel tank according to an embodiment of the present invention.

[0035] Figure 5 This is a partial schematic diagram of the arrangement structure of the fuel tank fuel quantity measurement system in the aircraft wing fuel tank according to an embodiment of the present invention.

[0036] Figure 6 Schematic diagram of an equivalent physical model of measuring capacitance in a fuel tank fuel level measurement system according to an embodiment of the present invention.

[0037] Figure 7 This is a principle block diagram of a fuel tank oil level measurement system according to an embodiment of the present invention.

[0038] Figure 8 This is a CV characteristic curve diagram of the fuel tank fuel level measurement system according to an embodiment of the present invention.

[0039] in:

[0040] 11. P-pole capacitor film, 12. N-pole capacitor film, 101. metal film layer, 102. insulating film layer, 103. shielding wire;

[0041] 20. Fuel tank, 21. Left wing fuel tank, 22. Right wing fuel tank. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0043] In order to solve the problem of measurement dead zone in traditional distributed measurement systems, usage restrictions are often set for the measurement systems. For example, the takeoff and descent attitudes are set to no more than ±6 degrees, and the cruise attitude is set to no more than ±4 degrees. When the flight attitude exceeds the above usage restrictions, the measurement system will perform limit processing, which greatly reduces the versatility of the measurement system.

[0044] To address the complex system architecture and operational limitations of distributed measurement systems, this paper proposes a measurement system that uses a capacitive film to sense changes in the fuel coverage area to measure the volume of fuel in a fuel tank. This system utilizes the properties of a capacitive film that maintains the same area of coverage for the same volume of fuel under different flight attitudes, and the linear correlation between the capacitive film coverage area and the output capacitance value. This system enables precise measurement of fuel levels in aircraft wing tanks without measurement dead zones. The system requires few components, exhibits a simple structure, and offers high reliability.

[0045] In some embodiments of the present invention, a fuel tank oil level measurement system includes a measuring capacitor, wherein the measuring capacitor includes a P-pole capacitor film and an N-pole capacitor film, wherein the P-pole capacitor film and the N-pole capacitor film are respectively disposed on two side walls of the fuel tank opposite to each other;

[0046] The P-pole capacitor film and the N-pole capacitor film can sense the contact with the fuel, so that the capacitance value of the measuring capacitor can change with the change of the fuel coverage area;

[0047] The oil amount in the tank is measured according to the capacitance value of the measuring capacitor.

[0048] Reference Figure 3 and Figure 4 Taking an aircraft wing fuel tank as an example, the aircraft wing fuel tank 20 is typically divided into multiple compartments by spaced ribs. In some embodiments of the present invention, a fuel tank fuel level measurement system includes a measuring capacitor, which includes a measuring subunit disposed in each fuel tank compartment. The measuring subunit includes a P-pole capacitor film 11 and an N-pole capacitor film 12, which are disposed on opposite side walls of the compartment.

[0049] The P-pole and N-pole capacitor films sense contact with the fuel, allowing the capacitance of each measuring subunit to change with the fuel coverage area. The fuel coverage area refers to the area submerged in and covering the P-pole and N-pole capacitor films.

[0050] The oil amount in the tank is measured according to the capacitance value of the measuring capacitor.

[0051] Reference Figure 3 、 Figure 4 and Figure 6In this embodiment, a P-pole capacitor film and an N-pole capacitor film are respectively set on the two opposite side walls of each compartment. At this time, the P-pole capacitor film and the N-pole capacitor film set opposite to each other in the compartment constitute a measuring subunit, and the measuring subunits in each compartment constitute a measuring capacitor, which is equivalent to a multi-layer parallel plate capacitor.

[0052] The P-pole capacitor film and the N-pole capacitor film are sensitive elements that can sense fuel. They can sense the coverage of the capacitor film by fuel and output corresponding capacitance values according to the coverage area of the fuel.

[0053] At this time, by establishing a relationship between the capacitance value of the measuring capacitor and the oil level in the fuel tank, the oil level in the fuel tank can be obtained based on the measurement of the capacitance value.

[0054] Through research, it is found that the theoretical capacitance C of the measured capacitance using P-pole capacitor film and N-pole capacitor film is mea The relationship between the fuel coverage area satisfies the following equation:

[0055]

[0056] Among them, ε1 represents the dielectric constant of fuel, ε0 represents the dielectric constant of air, and K is the electrostatic force constant (9×10 9 ), d is the distance between adjacent P-pole capacitor films and N-pole capacitor films in the fuel tank or fuel tank compartment, S 总 is the total area of all P-pole capacitor films and N-pole capacitor films, S1 is the area of P-pole capacitor films and N-pole capacitor films covered by fuel, and N is the number of capacitors composed of one P-pole capacitor film and one N-pole capacitor film, that is, the number of capacitors in the multilayer parallel plate capacitor.

[0057] When the fuel tank specifications are determined, d is a fixed value, and the theoretical capacitance value C of the measured capacitance can be obtained by formula 1) mea It is linearly related to the fuel coverage area S1.

[0058] Arranging formula 1) yields:

[0059]

[0060] Taking a single compartment of a fuel tank as an example, the number of capacitors constituting a multilayer parallel plate capacitor is 1, that is, N=1.

[0061] The theoretical capacitance value of the capacitor in a single compartment is obtained by formula 2:

[0062]

[0063] Generally speaking, the volume of fuel in a compartment can be approximately expressed as:

[0064]

[0065] According to formula 3) and formula 4), we can get:

[0066]

[0067] Among them, V 单个隔舱 is the volume of fuel in the compartment, C 单个隔舱 mea is the theoretical capacitance value of the capacitor composed of the P-pole capacitor film and the N-pole capacitor film in the compartment, V 总 is the volume of the compartment.

[0068] When the fuel tank size and the type and brand of the fuel to be tested are determined, the formula (5) are constant values respectively. It can be seen that the volume of fuel in the compartment is linearly related to the theoretical capacitance value of the measured capacitor.

[0069] When the aircraft's flight attitude changes, the oil surface distribution in the fuel tank compartment changes accordingly. Since the P-pole capacitor film and the N-pole capacitor film are arranged oppositely on the two side walls of the compartment, the change in the oil surface distribution will only change the shape of the oil surface distribution, and the area covered by the fuel on the P-pole capacitor film and the N-pole capacitor film will not change.

[0070] At this time, the theoretical capacitance C based on the measured capacitance mea The linear correlation with the fuel coverage area and the fact that the fuel coverage area does not change with attitude changes enable the measurement of fuel tank quantity in any flight attitude. Without considering the influence of flight attitude, the measurement system has greater applicability and versatility.

[0071] Since the measurement system is not affected by the flight attitude, there is no need to obtain flight attitude data during measurement. Less data needs to be processed, the oil measurement algorithm is simpler, and the reliability and accuracy of the measurement data are higher.

[0072] Reference Figure 4 and Figure 5 The P-type capacitor film 11 and the N-type capacitor film 12 each include a metal film layer 101 and insulating film layers 102 disposed on either side of the metal film layer. The insulating film layers disposed on either side of the metal film layer are used to isolate the metal film layer from the side walls of the compartment and the external environment.

[0073] The P-pole capacitor film and the N-pole capacitor film are designed to conform to the shape of the compartment sidewall, so that the P-pole capacitor film and the N-pole capacitor film can cover the entire surface of the compartment sidewall. The P-pole capacitor film and the N-pole capacitor film can be applied to the surface of the compartment sidewall by adhesive coating.

[0074] Reference Figure 7In some embodiments, the fuel tank oil level measurement system includes a signal processing unit, which is electrically connected to the P-pole capacitor film and the N-pole capacitor film, and is used to obtain the capacitance value of the measuring capacitor and calculate the fuel tank oil level based on the capacitance value.

[0075] The P-pole capacitor film 11 and the N-pole capacitor film 12 of each measuring subunit are respectively connected to the signal processing unit via shielded wires 103. Specifically, the shielded wires are connected to the metal film layers of the P-pole capacitor film and the N-pole capacitor film.

[0076] This measurement system, which uses capacitive film as the sensing element, is lightweight and can be directly adhered to the side wall of the fuel tank. It does not require any other mechanical connection structures and is easy to install and connect. Its service life far exceeds the aircraft's service life (generally up to 30 years), reducing aircraft maintenance costs and aircraft failure rates.

[0077] As an embodiment, the signal processing unit includes an excitation module, a signal processing module and a data processing module;

[0078] The excitation module is electrically connected to the P-pole capacitor film and is used to output an AC excitation signal to the P-pole capacitor film;

[0079] The signal processing module is electrically connected to the N-pole capacitor film and is used to collect the output current signal and process the current signal to convert the current signal into a digital value;

[0080] The data processing module is electrically connected to the signal processing module and is used to calculate the capacitance value of the measuring capacitor according to the processed current signal and calculate the oil amount in the fuel tank according to the capacitance value.

[0081] The measurement system uses an AC signal for excitation, with an excitation current in the microampere range. The steady-state energy introduced into the fuel tank is in the nanojoule range, meeting the Civil Aviation Administration of China's AC 25.981 fuel tank safety protection airworthiness regulations.

[0082] Using a capacitive film as the measuring element, damage to the measuring element under impact from drops and collisions will not pose a risk of penetrating the fuel tank, nor will it damage the fuel supply pipeline. This meets the CCAR-25 standard for fuel tank explosion-proof protection under aircraft crash conditions and provides a high level of intrinsic safety.

[0083] The capacitance value of the measuring capacitor and the fuel tank oil level data are collected, a mapping relationship between the capacitance value and the fuel tank oil level is established, and a CV fuel tank characteristic database is constructed; the data processing module can obtain the fuel tank oil level based on the constructed CV fuel tank characteristic database and the capacitance value.

[0084] The capacitance value of the measuring subunit of each compartment is collected by the signal processing unit, and the capacitance value C0 when the fuel tank is empty and the capacitance value C when the fuel tank is full are measured respectively.m , through linear interpolation, the capacitance can be obtained as C mea The fuel volume in the fuel tank is measured at the same time to realize the measurement of the fuel volume in the fuel tank.

[0085] At the same time, in order to reduce the theoretical error caused by the calculation of the above formula, the installed fuel quantity measurement system is subjected to an oil quantity calibration test of unit volume ΔV and capacitance change ΔC to determine the truth table between the measured capacitance value C and the actual fuel volume V, which is pre-stored in the signal processing unit. A more accurate fuel volume can be obtained by looking up the table.

[0086] Reference Figure 1 , the measurement system of the present invention is further described with reference to specific examples.

[0087] According to the shape of the side wall of the fuel tank compartment, the P-pole capacitor film and the N-pole capacitor film are designed in the same way. The surface area of the capacitor film is 0.593m 2 The distance between the P-pole capacitor film and the N-pole capacitor film in the compartment is 0.5m.

[0088] Reference Figure 5 , P-pole capacitor films and N-pole capacitor films are adhered to the side walls of each compartment in the left wing fuel tank 21 and the right wing fuel tank 22, and shielded wires are welded to the metal film layers of each capacitor film. Each P-pole capacitor film is connected together through a shielded wire, and each N-pole capacitor film is connected together through another shielded wire to form a multi-layer parallel plate capacitor. Then, the shielded wires are respectively connected to the signal processing unit, and the shielding layer of the shielded wire is connected to the ground terminal of the signal processing unit.

[0089] The measured capacitance obtained forms an empty fuel tank capacitance value of about 420pF when the fuel tank is empty. When the fuel dielectric constant is 2.13, the capacitance value when the fuel tank is full is 894.6pF.

[0090] Taking the total capacity of the fuel tank as 1000L as an example, every 1pF change in capacitance means a change of 2.1L in the volume of fuel in the tank.

[0091] The signal processing unit has a calibration function. Before the first installation, the fuel tank is calibrated with fuel at intervals of 10L to calibrate the characteristic curve between the capacitance value C of the measuring capacitor and the fuel volume V in the tank, such as Figure 8 As shown, the characteristic curve is stored in the signal processing unit in the form of a database to generate a CV fuel tank characteristic database.

[0092] When measuring the fuel level in the fuel tank, the signal processing unit generates an AC excitation signal to the P-pole capacitor film through the excitation module, picks up the current signal fed back by the N-pole capacitor film through the signal processing module, processes and converts it into a digital quantity, and then outputs it to the data processing module. The data processing module converts the digital quantity into a capacitance value, and the capacitance value obtained is 657.3pF; by querying the two groups of data (653, 490) and (658, 500) in the CV fuel tank characteristic database, using linear interpolation method, it is obtained that the fuel volume in the fuel tank represented by 657.3pF is 498.6L, and the current fuel level in the fuel tank is calculated.

[0093] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. used to indicate the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the present invention.

[0094] Furthermore, the use of terms such as "horizontal" and "vertical" in the description of the present invention does not necessarily imply that the component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical" and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0095] It should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0096] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the scope of protection of the present invention.

Claims

1. Fuel tank oil level measurement system, characterized in that, The measuring capacitor includes a P-pole capacitor film and an N-pole capacitor film, and the P-pole capacitor film and the N-pole capacitor film are respectively arranged on the side walls of the fuel tank opposite to each other; The P-pole capacitor film and the N-pole capacitor film can sense contact with the fuel, so that the capacitance value of the measuring capacitor can change with the change of the fuel coverage area; The oil amount in the tank is measured according to the capacitance value of the measuring capacitor.

2. The fuel tank oil level measurement system according to claim 1, characterized in that: The measuring capacitor includes a measuring subunit arranged in each fuel tank compartment, and the measuring subunit includes a P-pole capacitor film and an N-pole capacitor film, and the P-pole capacitor film and the N-pole capacitor film are respectively arranged on the two side walls of the compartment opposite to each other.

3. The fuel tank oil level measurement system according to claim 1 or 2, characterized in that: The P-pole capacitor film and the N-pole capacitor film both include a metal film layer and insulating film layers arranged on both sides of the metal film layer.

4. The fuel tank oil level measurement system according to claim 1 or 2, characterized in that: The P-pole capacitor film and the N-pole capacitor film are adhered and arranged on the entire surface of the side wall of the compartment.

5. The fuel tank oil level measurement system according to claim 1 or 2, characterized in that: The theoretical capacitance value of the measuring capacitor and the fuel coverage area satisfy the following relationship: Wherein, ε1 represents the dielectric constant of fuel, ε0 represents the dielectric constant of air, K is the electrostatic force constant, d is the distance between adjacent P-pole capacitor films and N-pole capacitor films in the fuel tank or fuel tank compartment, Stotal is the total area of all P-pole capacitor films and N-pole capacitor films, S1 is the area of P-pole capacitor films and N-pole capacitor films covered by fuel, and N is the number of capacitors formed by one P-pole capacitor film and one N-pole capacitor film.

6. The fuel tank oil level measurement system according to claim 1 or 2, characterized in that: It also includes a signal processing unit, which is electrically connected to the P-pole capacitor film and the N-pole capacitor film and is used to obtain the capacitance value of the measuring capacitor and calculate the oil amount in the tank based on the capacitance value.

7. The fuel tank oil level measurement system according to claim 6, characterized in that: The P-pole capacitor film and the N-pole capacitor film of each measuring sub-unit are respectively connected to the signal processing unit through shielded wires.

8. The fuel tank oil level measurement system according to claim 6, characterized in that: The signal processing unit includes an excitation module, a signal processing module and a data processing module; The excitation module is electrically connected to the P-pole capacitor film and is used to output an AC excitation signal to the P-pole capacitor film; The signal processing module is electrically connected to the N-pole capacitor film and is used to collect the output current signal and process the current signal; The data processing module is electrically connected to the signal processing module, and is used to calculate the capacitance value of the measuring capacitor according to the processed current signal and calculate the oil amount in the fuel tank according to the capacitance value.

9. The fuel tank oil level measurement system according to claim 8, characterized in that: Also included is a CV fuel tank characteristic database, the CV fuel tank characteristic database including mapping relationship data between capacitance values and fuel tank oil levels; The data processing module calculates the fuel volume in the fuel tank according to the CV fuel tank characteristic database and the capacitance value.

Images