Fuel tank oil level detection method and device

Abstract

A fuel tank oil level detection device is provided, comprising multiple light beam emitters and a photosensitive element disposed on the inner surface of the top wall of the fuel tank; the multiple light beam emitters are arranged in a circular array, and the photosensitive element is disposed at the center of the circular array formed by the multiple light beam emitters; the light beams emitted by each light beam emitter have a fixed deviation angle with the normal direction of the fuel tank bottom wall; the light beams emitted by the multiple light beam emitters are refracted by the oil to form multiple light spots on the bottom wall of the fuel tank; the photosensitive element is used to capture the light spots and transmit the light spot position information to a vehicle processor. A fuel tank oil level detection method, utilizing the above-mentioned fuel tank oil level detection device, comprises the following steps: using the light beams emitted by the light beam emitters to form refracted light beams after passing through the oil, and forming multiple light spots on the bottom wall of the fuel tank; using the photosensitive element to capture the light spots and transmit the light spot position information to a vehicle processor; and calculating the oil depth and oil volume ratio based on the light spot position information.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid level measurement, and in particular to a method and device for detecting the oil level of an oil tank. Background Art

[0002] In various fields where fuel tanks are used, particularly in machinery, the primary method for measuring oil level in fuel tanks is currently to measure the oil level by varying the resistance. This method requires the oil level sensor to be directly inserted into the oil. The sensor's overall length must be proportional to the tank's depth, necessitating the selection of an appropriate sensor or custom design when designing the fuel tank. Furthermore, when purchasing and repairing oil level sensors, strict specifications must be adhered to. This results in poor versatility, making them difficult to purchase and use, and resulting in a high failure rate. Other oil level sensors, such as ultrasonic sensors, are currently available, but they suffer from low accuracy and high cost, leading to their low adoption.

[0003] In addition, patent CN112816028A discloses a liquid level measurement device, a fuel tank, and a vehicle. The liquid level measurement method uses a detection strip installed at the bottom of the fuel tank to detect the position of a light spot and then calculate the liquid level. However, this method has two significant drawbacks: first, the measurement accuracy is low. When the fuel tank is tilted, the oil level remains horizontal, and the oil is also tilted relative to the tank, resulting in erroneous measurements according to this patent. Furthermore, the large number of light sensors installed at the bottom of the fuel tank is costly, unreliable, and impractical. Summary of the Invention

[0004] The main purpose of the present invention is to provide a method and device for detecting the oil level in a fuel tank, aiming to solve the above technical problems.

[0005] To achieve the above object, the present invention proposes

[0006] A fuel tank oil level detection device, comprising an oil level sensor provided on the top wall of the fuel tank, the oil level sensor comprising a plurality of light beam emitters and a photosensitive element; the plurality of light beam emitters are distributed in a circular array, and the photosensitive element is provided at the center of the circular array formed by the plurality of light beam emitters; the light beams emitted by each light beam emitter have a fixed deviation angle with the normal direction of the bottom wall of the fuel tank; the light beams emitted by the plurality of light beam emitters are refracted by the oil to form a plurality of light spots on the bottom wall of the fuel tank; the photosensitive element is used to capture the light spots and transmit the light spot position information to a vehicle processor, which calculates the oil depth and oil volume ratio.

[0007] Preferably, the inner surface of the bottom wall of the oil tank is planar.

[0008] Preferably, the number of the light beam emitters is an even number, and the number of light beam emitters is ≥8.

[0009] Preferably, the oil level sensor further includes a flange, and the light beam emitter and the photosensitive element are mounted on the inner surface of the top wall of the oil tank via the flange.

[0010] Preferably, a first cylinder is provided at the lower end of the flange, and a second cylinder is provided at the lower end of the first cylinder; the diameter of the second cylinder is smaller than the diameter of the first cylinder, and a limiting surface is formed between the second cylinder and the first cylinder; a plurality of light beam emitters are distributed on the outer cylindrical surface of the second cylinder, and the upper ends of the light beam emitters are against the limiting surface; an accommodating countersunk hole is provided at the center of the lower end surface of the second cylinder, and the photosensitive element is installed in the accommodating countersunk hole.

[0011] Preferably, the outer cylindrical surface of the second cylinder is a conical shape with a cross-sectional diameter gradually increasing from top to bottom, and the light beam emitter is placed on the outer cylindrical surface of the second cylinder so that there is a fixed angle between the axis of the light beam emitter and the normal direction of the bottom wall of the oil tank.

[0012] The present invention also provides a method for detecting the oil level in a fuel tank, which uses a fuel tank oil level detection device and includes the following steps:

[0013] Step S1: A light beam emitted by a light beam emitter forms a refracted light beam after passing through the oil, and forms a plurality of light spots on the bottom wall of the oil tank;

[0014] Step S2: Capturing the light spot using a photosensitive element and transmitting the position information of the light spot to a vehicle processor;

[0015] Step S3: The vehicle processor calculates the oil depth and oil volume ratio based on the position information of the light spot.

[0016] Preferably, in step S3, when the oil tank is in a horizontal state, each light spot is fitted to obtain a fitting light ring, and the oil depth h and the oil volume ratio i are calculated according to the radius R of the fitting light ring according to the following formula:

[0017] Oil depth

[0018] Oil volume ratio

[0019] Where: r0 is the distance between the light beam emitter and the photosensitive element;

[0020] H1 is the distance between the lower end of the beam emitter of the annular array and the bottom wall of the fuel tank;

[0021] H0 is the distance between the photosensitive element and the bottom wall of the fuel tank;

[0022] a is the deviation angle between the beam emitter and the normal direction of the tank bottom wall;

[0023] n is the refractive index of air to oil.

[0024] Preferably, in step S3, when the fuel tank is tilted and the fuel level sensor is arranged at the geometric center of the top wall of the fuel tank, the projection point of the fuel level sensor in the direction perpendicular to the bottom wall of the fuel tank is taken as the center point, an inscribed circle is drawn through the center point and is tangent to the light point closest to the center point, and the radius of the inscribed circle is taken as R2; then a circumscribed circle is drawn through the center point and is tangent to the light point farthest from the center point, and the radius of the circumscribed circle is taken as R1; and the calculation is performed according to the following formula:

[0025]

[0026]

[0027] at this time:

[0028]

[0029] Where: h1 is the distance between the incident point of the light beam at the oil surface corresponding to the light point farthest from the center point and the bottom wall of the oil tank;

[0030] h2 is the distance between the incident point of the light beam corresponding to the light spot closest to the center point at the oil surface and the bottom wall of the oil tank;

[0031] r0 is the distance between the light beam emitter and the photosensitive element;

[0032] H1 is the distance between the lower end of the beam emitter of the annular array and the bottom wall of the fuel tank;

[0033] H0 is the distance between the photosensitive element and the bottom wall of the fuel tank;

[0034] a is the deviation angle between the beam emitter and the normal direction of the tank bottom wall;

[0035] n is the refractive index of air to oil.

[0036] Preferably, in step S3, when the fuel tank is tilted and the fuel level sensor is arranged at a non-geometric center of the fuel tank top wall, the projection point of the fuel level sensor in a direction perpendicular to the fuel tank bottom wall is taken as the center point, an inscribed circle is drawn through the center point and is tangent to the light point closest to the center point, and the radius of the inscribed circle is taken as R2; then a circumscribed circle is drawn through the center point and is tangent to the light point farthest from the center point, and the radius of the circumscribed circle is taken as R1; and the calculation is performed according to the following formula:

[0037]

[0038] L1=(h0-h1)·tanα+r0

[0039] L2=(h0-h2)·tanα+r0

[0040]

[0041] Δh=w·tanθ

[0042] Fake oil depth

[0043] at this time:

[0044] h=h′+Δh

[0045]

[0046] Where: h1 is the distance between the incident point of the light beam at the oil surface corresponding to the light point farthest from the center point and the bottom wall of the oil tank;

[0047] h2 is the distance between the incident point of the light beam corresponding to the light spot closest to the center point at the oil surface and the bottom wall of the oil tank;

[0048] r0 is the distance between the light beam emitter and the photosensitive element;

[0049] H1 is the distance between the lower end of the beam emitter of the annular array and the bottom wall of the fuel tank;

[0050] H0 is the distance between the photosensitive element and the bottom wall of the fuel tank;

[0051] a is the deviation angle between the beam emitter and the normal direction of the tank bottom wall;

[0052] n is the refractive index from air to oil;

[0053] A and B are the distances between the oil level sensor and the geometric center of the top wall of the fuel tank in the length direction and width direction respectively;

[0054] L1 is the distance between the incident point of the light beam at the oil surface corresponding to the light point farthest from the center point and the line connecting the oil level sensor and the center point;

[0055] L2 is the distance between the incident point of the light beam corresponding to the light point closest to the center point at the oil surface and the line connecting the oil level sensor and the center point;

[0056] θ is the tilt angle of the fuel tank;

[0057] Definition of δ: The angle formed by taking the center of the oil level sensor as the 0 point, the direction from the bottom to the top of the tank wall as the +Y direction, and the direction from the nearest light spot to the farthest light spot as the vector direction, starting from the +Y direction in a counterclockwise direction and ending at the vector direction.

[0058] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0059] The detection method and device provided by the present invention are non-contact oil level measurement methods that utilize the principles of optical imaging and the refraction of light propagating through different media to determine the oil level. They offer high reliability and responsiveness. During oil level measurement, an annular light beam is used to eliminate errors caused by tank tilt, ensuring accurate and reliable measurement results. Furthermore, oil level measurement can be programmably controlled to a higher degree, enabling continuous oil level measurement or measurements at set intervals. The overall measurement device offers low cost, high reliability, responsiveness, ease of installation and maintenance, and the ability to achieve standardized serialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0061] Figure 1 A schematic diagram of the light beam emitter and light sensing element after being installed on the fuel tank in the present invention;

[0062] Figure 2 A schematic structural diagram of the oil level sensor in the present invention;

[0063] Figure 3 This is a three-dimensional effect diagram showing the oil level detection when the oil tank is in a horizontal state;

[0064] Figure 4 This is a schematic diagram of the light ring fitted by the light spot on the bottom wall of the fuel tank when the fuel tank is in a horizontal state;

[0065] Figure 5 This is a schematic diagram of light beam refraction during oil level detection when the oil tank is in a horizontal state;

[0066] Figure 6 This is a schematic diagram of the structure when the fuel tank is in a tilted state and the fuel level sensor is arranged at the geometric center of the top wall of the fuel tank;

[0067] Figure 7 Schematic diagram of light beam refraction during oil level detection when the oil tank is in an inclined state and the oil level sensor is arranged at the geometric center of the top wall of the oil tank;

[0068] Figure 8 It is the combination of light spots at the bottom of the fuel tank when the fuel tank is in a tilted state and the fuel level sensor is arranged at the geometric center of the top wall of the fuel tank;

[0069] Figure 9 This is the light spot fitting pattern when the fuel tank is in a tilted state and the fuel level sensor is arranged at the geometric center of the top wall of the fuel tank;

[0070] Figure 10 This is a schematic diagram of the oil level sensor being arranged at a non-geometric center of the top wall of the oil tank;

[0071] Figure 11 Schematic diagram of light beam refraction during oil level detection when the oil tank is tilted and the oil level sensor is arranged at a non-geometric center of the tank top wall.

[0072] Among them: 100-bit sensor; 1-oil tank; 2-light beam emitter; 201-light beam; 202-refracted light beam; 203-light spot; 204-fitting light ring; 3-photosensitive element; 4-oil; 5-flange; 501-first column; 502-second column; 503-limiting surface; 504-accommodating countersunk hole. DETAILED DESCRIPTION

[0073] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0074] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0075] In addition, the descriptions of "first", "second", etc. in the present invention are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0076] Combine Figure 1 and Figure 2As shown, a fuel tank oil level detection device is provided with an oil level sensor 100 on the top wall of the fuel tank 1, and the fuel level sensor 100 includes multiple light beam emitters 2 and a photosensitive element 3; the multiple light beam emitters 2 are distributed in a circular array, and the photosensitive element 3 is arranged at the center position of the circular array formed by the multiple light beam emitters 2; the light beams emitted by each light beam emitter 2 have a fixed deviation angle with the normal direction of the bottom wall of the fuel tank 2; the light beams emitted by the multiple light beam emitters 2 are refracted by the oil 4 to form multiple light spots on the bottom wall of the fuel tank 2; the photosensitive element 3 is used to capture the light spots and transmit the light spot position information to the vehicle processor, and the vehicle processor calculates the oil depth and oil volume ratio.

[0077] In the present invention, the inner surface of the bottom wall of the fuel tank 1 is flat. This structure facilitates the formation of light spots 203 on the same plane. The number of the light beam emitters 2 is an even number, and the number of light beam emitters 2 is ≥8.

[0078] Combine Figure 2 As shown, the oil level sensor 100 also includes a flange 5, through which the light beam emitter 2 and the photosensitive element 3 are mounted on the inner surface of the top wall of the oil tank 1. A first column 501 is provided at the lower end of the flange 5, and a second column 502 is provided at the lower end of the first column 501. The diameter of the second column 502 is smaller than that of the first column 501, and a limiting surface 503 is formed between the second column 502 and the first column 501. Multiple light beam emitters 2 are evenly distributed on the outer surface of the second column 502, and the upper ends of the light beam emitters 2 abut against the limiting surface 503. The provision of the second column 502 facilitates the even distribution of the light beam emitters 2 in a circular array, and the limiting surface 503 ensures that each light beam emitter 2 is at the same horizontal height. In addition, a receiving countersunk hole 504 is provided at the center of the lower end surface of the second column 502, and the photosensitive element 3 is mounted in the receiving countersunk hole 504. The accommodating countersunk hole 504 is provided to facilitate installation of the photosensitive element 3 and to ensure that the photosensitive element 3 is located at the center of the annular array formed by the multiple light beam emitters 2 .

[0079] Furthermore, in this embodiment, the outer cylindrical surface of the second cylinder 502 is a conical shape with a cross-sectional diameter gradually increasing from top to bottom. The light beam emitter 2 is placed on the outer cylindrical surface of the second cylinder 502 so that there is a fixed angle between the axis of the light beam emitter 2 and the normal direction of the bottom wall of the oil tank 2.

[0080] Combine Figures 3 to 5 As another aspect of the present invention, a method for detecting the oil level in a fuel tank is provided, which uses the above-mentioned oil level detection device in the fuel tank, and includes the following steps:

[0081] Step S1: The light beam 201 emitted by the light beam emitter 2 passes through the oil 4 to form a refracted light beam 202, and a plurality of light spots 203 are formed on the bottom wall of the oil tank 2;

[0082] Step S2: using the photosensitive element 3 to capture the light spot 203 and transmitting the position information of the light spot 203 to the vehicle processor;

[0083] Step S3 : The onboard processor calculates the oil depth and oil volume ratio based on the position information of the light spot 203 .

[0084] In step S3, each light spot 203 is fitted to obtain a fitting light ring 204. According to the radius R of the fitting light ring 204, the oil depth h is calculated according to the following formula:

[0085]

[0086] Where: r0 is the distance between the light beam emitter 2 and the photosensitive element 3;

[0087] H1 is the distance between the lower end of the circular array beam emitter 2 and the bottom wall of the fuel tank 1;

[0088] H0 is the distance between the photosensitive element 3 and the bottom wall of the fuel tank 1;

[0089] a is the deflection angle between the beam emitter 2 and the normal direction of the bottom wall of the fuel tank 1;

[0090] n is the refractive index from air to oil;

[0091]

[0092] Where: h is the oil depth;

[0093] H0 is the distance between the photosensitive element 3 and the bottom wall of the fuel tank 1.

[0094] Combine Figures 6 to 9 As shown, in step S3, when the fuel tank 1 is tilted and the fuel level sensor 100 is arranged at the geometric center of the top wall of the fuel tank 1, the projection point of the fuel level sensor 100 in the direction perpendicular to the bottom wall of the fuel tank is taken as the center point, an inscribed circle is drawn through the center point and is tangent to the light point closest to the center point, and the radius of the inscribed circle is taken as R2; then a circumscribed circle is drawn through the center point and is tangent to the light point farthest from the center point, and the radius of the circumscribed circle is taken as R1; it is calculated according to the following formula:

[0095]

[0096] at this time:

[0097]

[0098]

[0099] Where: h1 is the distance between the incident point of the light beam at the oil surface corresponding to the light point farthest from the center point and the bottom wall of the oil tank;

[0100] h2 is the distance between the incident point of the light beam corresponding to the light spot closest to the center point at the oil surface and the bottom wall of the oil tank;

[0101] r0 is the distance between the light beam emitter 2 and the photosensitive element 3;

[0102] H1 is the distance between the lower end of the annular array beam emitter 2 and the bottom wall of the fuel tank 1;

[0103] H0 is the distance between the photosensitive element 3 and the bottom wall of the fuel tank 1;

[0104] a is the deflection angle between the beam emitter 2 and the normal direction of the bottom wall of the fuel tank 1;

[0105] n is the refractive index of air to oil.

[0106] Combine Figure 10 and Figure 11 As shown, in step S3, when the fuel tank 1 is tilted and the fuel level sensor 100 is arranged at a non-geometric center of the top wall of the fuel tank 1, the projection point of the fuel level sensor 100 in the direction perpendicular to the bottom wall of the fuel tank is taken as the center point, an inscribed circle is drawn through the center point and is tangent to the light point closest to the center point, and the radius of the inscribed circle is taken as R2; a circumscribed circle is drawn through the center point and is tangent to the light point farthest from the center point, and the radius of the circumscribed circle is taken as R1; and the calculation is performed according to the following formula:

[0107]

[0108] L1=(h0-h1)·tanα+r0

[0109] L2=(h0-h2)·tanα+r0

[0110]

[0111] Δh=w·tanθ

[0112] Fake oil depth

[0113] at this time:

[0114] h=h′+Δh

[0115]

[0116] Where: h1 is the distance between the incident point of the light beam at the oil surface corresponding to the light point farthest from the center point and the bottom wall of the oil tank;

[0117] h2 is the distance between the incident point of the light beam corresponding to the light spot closest to the center point at the oil surface and the bottom wall of the oil tank;

[0118] r0 is the distance between the light beam emitter 2 and the photosensitive element 3;

[0119] H1 is the distance between the lower end of the circular array beam emitter 2 and the bottom wall of the fuel tank 1;

[0120] H0 is the distance between the photosensitive element 3 and the bottom wall of the fuel tank 1;

[0121] a is the deflection angle between the beam emitter 2 and the normal direction of the bottom wall of the fuel tank 1;

[0122] n is the refractive index from air to oil;

[0123] A and B are the distances between the oil level sensor 100 and the geometric center of the top wall of the fuel tank 1 in the length direction and the width direction respectively;

[0124] L1 is the distance between the incident point of the light beam at the oil level corresponding to the light point farthest from the center point and the line connecting the oil level sensor 100 and the center point;

[0125] L2 is the distance between the incident point of the light beam corresponding to the light point closest to the center point at the oil surface and the line connecting the oil level sensor 100 and the center point;

[0126] θ is the tilt angle of the fuel tank;

[0127] Definition of δ: The angle formed by moving counterclockwise from the +Y direction to the end of the vector direction, with the center of the fuel level sensor as the zero point, the direction from the bottom to the top of the fuel tank wall as the +Y direction, and the direction from the nearest light spot to the farthest light spot as the vector direction. The angle δ is automatically determined by the system based on the image.

[0128] The oil level measured when the oil tank 1 is in a horizontal state is the real oil level, and the oil level measured when the oil tank 1 is in an inclined state is a false oil level, which needs to be corrected according to the arrangement position of the oil level sensor 100.

[0129] In the present invention, the bottom wall of the oil tank 1 is configured to be flat so that the light beam emitted by the light beam emitter 2 forms a light spot 203 after being refracted by the oil 4. The even number of light beam emitters 2 facilitates fitting the light spot 203 to form a fitting light ring 204, and also facilitates drawing an inscribed circle tangent to the light spot closest to the center point and a circumscribed circle tangent to the light spot farthest from the center point in step S3.

[0130] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformation made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A fuel tank oil level detection device, characterized in that: An oil level sensor (100) is provided on the top wall of the oil tank (1), and the oil level sensor (100) comprises a plurality of light beam emitters (2) and a light sensing element (3); The plurality of light beam emitters (2) are distributed in a ring array, and the photosensitive element (3) is arranged at the center of the ring array formed by the plurality of light beam emitters (2); The light beams emitted by each light beam emitter (2) have a fixed deflection angle with the normal direction of the bottom wall of the oil tank (2); The light beams emitted by the multiple light beam emitters (2) are refracted by the oil (4) to form multiple light spots on the bottom wall of the oil tank (2); the photosensitive element (3) is used to capture the light spots and transmit the light spot position information to the vehicle processor, and the vehicle processor calculates the oil depth and oil volume ratio.

2. The fuel tank oil level detection device according to claim 1, characterized in that: The inner surface of the bottom wall of the oil tank (1) is in a flat shape.

3. The fuel tank oil level detection device according to claim 1, characterized in that: The number of the light beam emitters (2) is an even number, and the number of the light beam emitters (2) is ≥8.

4. The fuel tank oil level detection device according to claim 1, characterized in that: The oil level sensor (100) further comprises a flange (5), and the light beam emitter (2) and the light sensing element (3) are mounted on the inner surface of the top wall of the oil tank (1) via the flange (5).

5. The fuel tank oil level detection device according to claim 4, characterized in that: A first column (501) is provided at the lower end of the flange (5), and a second column (502) is provided at the lower end of the first column (501); the diameter of the second column (502) is smaller than the diameter of the first column (501), and a limiting surface (503) is formed between the second column (502) and the first column (501); a plurality of light beam emitters (2) are evenly distributed on the outer cylindrical surface of the second column (502), and the upper ends of the light beam emitters (2) abut against the limiting surface (503); an accommodating countersunk hole (504) is provided at the center of the lower end surface of the second column (502), and the photosensitive element (3) is installed in the accommodating countersunk hole (504).

6. The fuel tank oil level detection device according to claim 5, characterized in that: The outer cylindrical surface of the second column (502) is in the shape of a cone with a gradually increasing cross-sectional diameter from top to bottom. The light beam emitter (2) rests on the outer cylindrical surface of the second column (502) so that a fixed angle exists between the axis of the light beam emitter (2) and the normal direction of the bottom wall of the oil tank (2).

7. A method for detecting the oil level in a fuel tank, characterized in that: The fuel tank oil level detection device according to any one of claims 1 to 5 comprises the following steps: Step S1: The light beam (201) emitted by the light beam emitter (2) passes through the oil (4) to form a refracted light beam (202), and a plurality of light spots (203) are formed on the bottom wall of the oil tank (2); Step S2: using the photosensitive element (3) to capture the light spot (203), and transmitting the position information of the light spot (203) to the vehicle processor; Step S3: The vehicle processor calculates the oil depth and oil volume ratio based on the position information of the light spot (203).

8. The method for detecting the oil level in a fuel tank according to claim 7, wherein: In step S3, when the oil tank (1) is in a horizontal state, each light spot (203) is fitted to obtain a fitting light ring (204), and based on the radius R of the fitting light ring (204), the oil depth h and the oil volume ratio i are calculated according to the following formula: Wherein: r0 is the distance between the light beam emitter (2) and the light sensing element (3); H1 is the distance between the lower end of the annular array light beam emitter (2) and the bottom wall of the oil tank (1); a is the deflection angle between the light beam emitter (2) and the normal direction of the bottom wall of the oil tank (1); n is the refractive index of air to oil.

9. The method for detecting the oil level in a fuel tank according to claim 7, wherein: In step S3, when the oil tank (1) is in an inclined state and the oil level sensor (100) is arranged at the geometric center of the top wall of the oil tank (1), the projection point of the oil level sensor (100) in a direction perpendicular to the bottom wall of the oil tank is taken as the center point, an inscribed circle is drawn through the center point and is tangent to the light point closest to the center point, and the radius of the inscribed circle is taken as R2; then a circumscribed circle is drawn through the center point and is tangent to the light point farthest from the center point, and the radius of the circumscribed circle is taken as R1; and the calculation is performed according to the following formula: at this time: Where: h1 is the distance between the incident point of the light beam at the oil surface corresponding to the light point farthest from the center point and the bottom wall of the oil tank; h2 is the distance between the incident point of the light beam corresponding to the light spot closest to the center point at the oil surface and the bottom wall of the oil tank; r0 is the distance between the light beam emitter (2) and the light sensing element (3); H1 is the distance between the lower end of the annular array light beam emitter (2) and the bottom wall of the oil tank (1); a is the deflection angle between the light beam emitter (2) and the normal direction of the bottom wall of the oil tank (1); n is the refractive index of air to oil.

10. The method for detecting the oil level in a fuel tank according to claim 7, wherein: In step S3, when the oil tank (1) is in an inclined state and the oil level sensor (100) is arranged at a non-geometric center of the top wall of the oil tank (1), the projection point of the oil level sensor (100) in a direction perpendicular to the bottom wall of the oil tank is taken as the center point, an inscribed circle is drawn through the center point and is tangent to the light point closest to the center point, and the radius of the inscribed circle is taken as R2; then a circumscribed circle is drawn through the center point and is tangent to the light point farthest from the center point, and the radius of the circumscribed circle is taken as R1; and the calculation is performed according to the following formula: L1=(h0-h1)·tanα+r0 L2=(h0-h2)·tanα+r0 Δh=w·tanθ at this time: h=h ′ +Δh Where: h1 is the distance between the incident point of the light beam at the oil surface corresponding to the light point farthest from the center point and the bottom wall of the oil tank; h2 is the distance between the incident point of the light beam corresponding to the light spot closest to the center point at the oil surface and the bottom wall of the oil tank; r0 is the distance between the light beam emitter (2) and the light sensing element (3); H1 is the distance between the lower end of the annular array light beam emitter (2) and the bottom wall of the oil tank (1); a is the deflection angle between the light beam emitter (2) and the normal direction of the bottom wall of the oil tank (1); n is the refractive index from air to oil; A and B are the distances between the oil level sensor (100) and the geometric center of the top wall of the oil tank (1) in the length direction and the width direction respectively; L1 is the distance between the incident point of the light beam corresponding to the light point farthest from the center point at the oil level and the line connecting the oil level sensor (100) and the center point; L2 is the distance between the incident point of the light beam corresponding to the light point closest to the center point at the oil level and the line connecting the oil level sensor (100) and the center point; θ is the tilt angle of the fuel tank; Definition of δ: The angle formed by taking the center of the oil level sensor as the 0 point, the direction from the bottom to the top of the tank wall as the +Y direction, and the direction from the nearest light spot to the farthest light spot as the vector direction, starting from the +Y direction in a counterclockwise direction and ending at the vector direction.

Images