Device and method for measuring quality of oil in engine sump

Abstract

The invention relates to a device and a method for measuring the quality of oil in an engine oil pan, aiming at solving the influence of bubbles in the oil on the measurement accuracy, the shell of the device is divided into three sections: the upper part and the lower part are made of 316L steel materials, the middle part is made of polybenzimidazole, and the upper part of the shell is provided with an oil inlet, an inclined plate, a defoaming hole, an exhaust pipe and a floater; it is ensured that large bubbles in oil are filtered and discharged; the middle silicone rubber deforms under the action of vibration, so that oil liquid is separated from bubbles; an oil sensing element and a one-way valve are installed on the lower portion, and one-way outflow of oil is guaranteed. After an engine is started, oil liquid with foam flows into the device, after two-stage defoaming treatment, the oil liquid slowly enters a measuring area, oil liquid parameters are measured through the sensing element, real-time monitoring in a foam-free environment is achieved, and the device has the advantages of being compact in structure and high in precision and real-time measurement, can be easily integrated into an existing system and is suitable for various motor vehicles. And efficient and accurate oil quality real-time monitoring is provided.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile engine lubricant quality monitoring, and specifically to an engine oil pan oil quality measuring device and method which can effectively eliminate measurement deviations caused by bubbles, significantly improve the accuracy and reliability of density, viscosity and other parameter detection, and ensure real-time and accurate monitoring of the lubricant state during automobile operation. Background Art

[0002] An oil sensor is a device used to monitor the properties of liquid media (such as lubricating oil and hydraulic oil) in real time. It is widely used in automobiles, industrial machinery and other fields. It can accurately measure key parameters such as temperature, pressure, viscosity and contamination level, provide instant data support, optimize maintenance plans, extend equipment life, and improve system reliability. In addition, oil condition monitoring helps reduce unexpected downtime, control maintenance costs, enhance operational safety, and reduce the amount of waste oil generated to achieve environmental benefits. However, the oil in the engine oil pan contains a large number of bubbles, which is an important factor affecting the measurement accuracy of the oil sensor. Due to the large difference in the physical properties of bubbles and liquid media, the density and viscosity measurement results are seriously distorted, making it difficult for online monitoring of oil quality to effectively guide the evaluation of lubricating oil conditions. Summary of the invention

[0003] In view of the shortcomings and deficiencies in the prior art, the present invention proposes an engine oil pan oil quality measurement device and method that can effectively eliminate the measurement deviation caused by bubbles, significantly improve the accuracy and reliability of density, viscosity and other parameter detection, and ensure real-time and accurate monitoring of the lubricating oil state during automobile operation.

[0004] The present invention is achieved by the following measures:

[0005] An engine oil pan oil quality measuring device is characterized in that it is provided with a shell, and the shell includes three parts: an upper part, a middle part, and a lower part. An oil inlet is provided at the top of the shell, a defoaming component is provided at the oil inlet, an air outlet is provided on the top side of the shell, a spring baffle is provided at the air outlet, an exhaust pipe is connected to the outside of the air outlet, an oil sensor is installed on the lower side wall of the shell, an oil outlet is provided at the bottom of the shell, and a one-way valve to prevent oil backflow is provided at the oil outlet. The middle part of the shell made of flexible material deforms and squeezes the fluid inside the shell under the vibration of the oil, so that bubbles float up, and the oil flows downward through the oil quality sensing element, so as to realize real-time and accurate monitoring of the lubricating oil status during vehicle operation.

[0006] The present invention calculates the frequencies of each vibration source in the automobile system, determines the main vibration mode of the three-degree-of-freedom vibration system of the vehicle oil detection, and then adjusts the shell structure parameters to make the natural frequencies of each order of the shell close to the vibration frequencies of the vibration sources, wherein the first 6 natural frequencies of the middle flexible structure of the shell are 0.5Hz, 1.0Hz, 1.5Hz, 2Hz, 10Hz, and 20Hz. The vibration source frequency is calculated and the main vibration mode of the system is determined as follows:

[0007] Let m1 be the mass of the entire vehicle, spring stiffness k1 and damping c1; let the engine mass m2 be the suspension system, mounting bracket and other mechanical connections between m1 and spring stiffness k2 and damping c2; let the support structure, fixture and dynamic characteristics of the oil itself between the oil tank and oil mass m3 and the engine m2 be spring stiffness k3 and damping c3; let the coordinates x1, x2 and x3 of m1, m2 and m3 away from the static stable position, the forces on each mass block are F1(t), F2(t) and F3(t); let the coordinates x1, x2 and x3 of m1, m2 and m3 away from the static stable position, the forces on each mass block are F1(t), F2(t) and F3(t);

[0008] The vibration differential equation of the vibration system in the x direction is as follows:

[0009] For m1: m1x1″=-c1x1′+c2(x2′-x1′)-k1x1+k2(x2-x1)+F1(t)(1),

[0010] For m2: m2x2″=-c2(x2′-x1′)+c3(x3′-x2′)-k2(x2-x1)+k3(x3-x2)+F2(t)(2),

[0011] For m3: m3x3″=-c3(x3′-x2′)-k3(x3-x2)+F3(t)(3),

[0012] After sorting,

[0013] For m1: m1x1″+(c1+c2)x1′-c2x2′+(k1+k2)x1-k2x2=F1(t)(4),

[0014] For m2: m2x2″+(c2+c3)x2′-c2x1′-c3x3′+(k2+k3)x2-k2x1-k3x3=F2(t)(5),

[0015] For m3: m3x3″+c3x3′-c3x2′+k3x3-k3x2=F3(t)(6),

[0016] The differential equation of the three-degree-of-freedom vibration system of vehicle oil detection is:

[0017]

[0018] The formula is simplified as:

[0019] MX″+CX′+KX={F(t)}(8),

[0020] Where M is the mass matrix C is the damping matrix K is the stiffness matrix X is the displacement matrix {F(t)} is the excitation force

[0021] For a damped three-degree-of-freedom vibration system, the coordinate transformation of the differential equation modal matrix φ is:

[0022] M φ X″+C φ X′+K φ X=F φ (9)

[0023] Where M φ is the modal mass matrix of the system, C φ is the modal damping matrix, K φ is the modal stiffness matrix, M φ and K φ They are all diagonal matrices. The damping matrix C obtained after coordinate transformation is φ =φ T Cφ, becomes the modal damping matrix,

[0024] After diagonalization, we get:

[0025]

[0026] The damping matrix is ​​a linear combination of the mass matrix and the stiffness matrix, namely:

[0027] C=αM+βK(11),

[0028] In the formula, α and β are coefficients;

[0029] It can be deduced that:

[0030]

[0031] The above modal damping matrix is ​​a diagonal matrix, and the damping is proportional damping;

[0032] The mass matrix, stiffness matrix, and damping matrix are diagonalized, and the equations are decoupled to obtain independent and uncoupled equations:

[0033]

[0034] In the formula, c pi is the i-th order modal damping coefficient, expressed as the damping ratio:

[0035]

[0036] Then we have:

[0037]

[0038] The solution for free vibration is:

[0039]

[0040] In the formula,

[0041] Transforming the response in the modal coordinates to the physical coordinates, the response of the system is:

[0042]

[0043] Then the main vibration mode of the system is:

[0044]

[0045] The vibration frequency of each vibration source is f = ω di / 2π, adjust the structural parameters of the shell to make the natural frequencies of each order of the shell close to the vibration frequency of the vibration source.

[0046] The defoaming component is provided at the oil inlet of the present invention, and a multi-stage defoaming component is adopted, including a defoaming plate and an inclined plate. When the oil flows in from the oil inlet on the top of the shell, it first passes through the defoaming plate, and the defoaming plate is composed of a corrosion-resistant metal mesh, the inner circle of the metal mesh is a small hole, and the outer circle is a large hole. Further, the inner circle aperture is 2mm, the outer circle aperture is 3mm, and the transition area aperture is 2.4mm; after the oil flows through the defoaming plate, it passes through the inclined plate to make the remaining small bubbles rise and gather. The inclined plate is inclined on the side wall of the oil inlet and is arranged in a funnel shape. The lower end of the inclined plate is connected to the dropper. Further, the inclination angle of the inclined plate is 60°. The length is 5mm; it finally enters the dropper, the inner diameter of the dropper is 5mm, the length is 16mm, and it is made of transparent polycarbonate material; the defoaming component can effectively intercept and break up larger bubbles to prevent them from directly entering the measuring device, reduce the measurement deviation caused by the presence of bubbles, and ensure the sensor's accurate detection of the physical properties of the oil. It uses an inclined plate to optimize the oil flow path, so that small bubbles that are not filtered by the defoaming plate are concentrated in the upper space, gradually gathering to form larger bubbles that rise to the top. The design of the inclined plate makes it easier for bubbles to float up and be discharged, while guiding the oil to flow smoothly downward, further improving the measurement accuracy of the device.

[0047] An air outlet is provided on the top side of the shell of the present invention, and the air outlet is arranged on the lower side of the oil inlet. The air outlet is connected to the first exhaust pipe. The air inlet end of the first exhaust pipe is provided with a spring baffle for closing / opening the first exhaust pipe. A second exhaust pipe is also provided. The lower end of the second exhaust pipe is connected to the defoaming component and is located at the oil inlet for timely discharging the gas filtered by the defoaming component. A spring baffle is also provided at the lower end of the second exhaust pipe. When the air pressure pushes open the spring baffle, the gas filtered by the defoaming component is discharged along the second exhaust pipe. Furthermore, the exhaust pipe is made of corrosion-resistant material, the exhaust pipe outlet extends out of the oil pan liquid level by about 30 mm, and is bent inward with a fine-pore baffle to prevent oil from splashing in. The upper ends of the first exhaust pipe and the second exhaust pipe are respectively connected to floats, so that they float with the rise and fall of the oil level in the oil tank through the float, ensuring that the exhaust pipe is always located above the oil and the air outlet is kept unobstructed. The float is made of solid buoyancy material.

[0048] The upper part of the shell of the present invention is made of 316L steel, with a height of 30mm, a top inlet diameter of 20mm, and a wall thickness of 4mm, which is the oil inlet area and the bubble gathering area; the middle part is 80mm high, 50mm inner diameter, and 2mm thick, and is made of elastic polybenzimidazole (PBI) material. It deforms under the combined action of the engine, vehicle speed changes, and oil damping effect, squeezes the internal space, and separates the air and oil; the lower part of the shell is made of 316L steel, with a height of 40mm, a top inlet diameter of 20mm, and a wall thickness of 4mm. A one-way valve and an oil sensor are installed at the oil outlet, wherein the one-way valve ensures that the liquid can only flow outward to prevent backflow.

[0049] The present invention also proposes a method for measuring the quality of oil in an engine oil pan, characterized in that, using the above-mentioned device for measuring the quality of oil in an engine oil pan, when the engine is not started, oil without foam flows in from the oil inlet, passes through the defoaming plate, the inclined plate and the dropper, and flows into the shell, the oil increases, and the bubbles are filtered out inside, resulting in an increase in gas pressure. When the opening pressure of the spring baffle is reached, the spring baffles at the air inlet ends of the first exhaust pipe and the second exhaust pipe are pushed open, and the gas is discharged from the first exhaust pipe and the second exhaust pipe, and the oil flows out through the oil outlet until the inside of the device reaches a balanced state, at which time the upper half of the device is filled with gas, and the lower half is filled with liquid, and the oil sensor measures and outputs density, viscosity and temperature;

[0050] When starting and entering the running state, foamy oil flows in from the oil inlet, passes through the defoaming plate to filter out large bubbles, and the inclined plate makes the remaining small bubbles rise and gather, and then enters the dropper and flows into the shell. The middle flexible shell of the shell vibrates and deforms under the combined action of vehicle vibration, engine vibration, road excitation and oil damping effect, squeezing the internal space of the shell and causing the residual bubbles to float. The oil after two-stage defoaming flows to the oil quality sensing element, and the oil sensor continuously measures the oil quality in a foam-free environment to realize online real-time monitoring of density, viscosity and temperature.

[0051] The present invention is suitable for monitoring the quality of lubricating oil in the engine oil pan under various working conditions, and is particularly suitable for application scenarios of real-time and accurate monitoring of the state of lubricating oil during the operation of a car. It is particularly suitable for the oil pan of a car engine, and can provide high-precision and reliable measurement results in a complex working environment. Compared with the prior art, a multi-stage defoaming structure is provided, in which the middle flexible component is deformed under the action of multiple vibration sources, squeezing the internal fluid so that the residual bubbles are discharged upward through the air outlet, and the oil flows downward through the measurement sensing area. The device is provided with a self-protection valve sheet to prevent the oil from entering the exhaust pipe, and a one-way valve is provided at the bottom of the device to prevent the backflow of oil with bubbles. The present invention is compact in design and easy to install, and can be conveniently integrated into the existing system architecture. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Attached Figure 1 It is a three-dimensional schematic diagram of the oil sensor device in the present invention.

[0053] Attached Figure 2 It is a cross-sectional view of the oil sensor device in the present invention.

[0054] Attached Figure 3 It is a partial enlarged view of the inclined plate and the defoaming holes in the present invention.

[0055] Attached Figure 4 It is a cross-sectional view of the installation position of the sensor in the present invention.

[0056] Attached Figure 5 It is a partial enlarged view of the one-way valve structure in the present invention.

[0057] Attached Figure 6 It is an overall cross-sectional view of the oil tank and the oil sensor device in the present invention.

[0058] Attached Figure 7 The figure is a comparison chart of the measurement results of the present invention and the measurement results of the prior art.

[0059] Attached Figure 8 It is a schematic diagram of the principle of the three-degree-of-freedom vibration system for vehicle oil detection in the present invention.

[0060] Figure numerals: oil pan 1, oil area and oil sensor installation area 2, oil quality sensing element 3, oil inlet 4, upper shell 5, middle flexible shell 6, lower shell 7, oil outlet 8, first exhaust pipe 9, float on first exhaust pipe 10, second exhaust pipe 11, float on second exhaust pipe 12, defoaming plate 13, inclined plate 14, oil 15, spring 16, baffle 17, spring in second spring baffle 18, baffle in second spring baffle 19, oil sensing element one 20, oil sensing element two 21, oil sensing element three 22, spring in one-way valve 23, one-way valve 24, one-way valve core 25, second exhaust pipe outlet 26, first exhaust pipe outlet 27. DETAILED DESCRIPTION

[0061] The implementation of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0062] Example:

[0063] This example proposes a device for monitoring the quality of lubricating oil in the engine oil pan suitable for various working conditions. Considering that a vehicle will generate various vibrations during operation, including engine vibration, vibration caused by speed changes, and bump vibration caused by uneven road surface, these vibrations are used to deform the flexible material to help separate the oil and bubbles. In this example, the middle part of the housing of the measuring device is made of flexible material. Under vibrations of different sources and characteristics (f = ωd i / 2π), the flexible part of the shell is deformed, which squeezes the internal fluid, causing the bubbles to float up, the oil to flow downward, and the bubbles are discharged through the exhaust hole;

[0064] This example makes full use of engine vibration (idle, medium speed, high speed), vehicle speed acceleration and deceleration shock, and vibration caused by uneven road surface, calculates the frequency characteristics of each vibration source, adjusts the device shell structure parameters, and makes its natural frequencies of each order close to the vibration frequency of the vibration source. The first 6 natural frequencies of the flexible structure of the device shell are measured to be 0.5Hz, 1.0Hz, 1.5Hz, 2Hz, 10Hz, and 20Hz.

[0065] Vibration source frequency calculation: as shown in the attached Figure 8 As shown, m1 is the mass of the entire vehicle, the spring stiffness k1 and the damping c1; the engine mass m2 and the suspension system, mounting bracket and other mechanical connections between m1 have spring stiffness k2 and damping c2; the support structure, fixing device and dynamic characteristics of the oil itself between the fuel tank and oil mass m3 and the engine m2 have spring stiffness k3 and damping c3.

[0066] m1, m2 and m3 leave the coordinates x1, x2 and x3 of the static stable position, and the forces on each mass block are F1(t), F2(t) and F3(t).

[0067] The vibration differential equation of this vibration system in the x direction is:

[0068] For m1: m1x1″=-c1x1′+c2(x2′-x1′)-k1x1+k2(x2-x1)+F1(t)

[0069] For m2: m2x2″=-c2(x2′-x1′)+c3(x3′-x2′)-k2(x2-x1)+k3(x3-x2)+F2(t)

[0070] For m3: m3x3″=-c3(x3′-x2′)-k3(x3-x2)+F3(t)

[0071] After sorting,

[0072] For m1: m1x1″+(c1+c2)x1′-c2x2′+(k1+k2)x1-k2x2=F1(t)

[0073] For m2: m2x2″+(c2+c3)x2′-c2x1′-c3x3′+(k2+k3)x2-k2x1-k3x3=F2(t)

[0074] For m3: m3x3″+c3x3′-c3x2′+k3x3-k3x2=F3(t)

[0075] The differential equation of the three-degree-of-freedom vibration system of vehicle oil detection is:

[0076]

[0077] The formula is simplified as:

[0078] MX″+CX′+KX={F(t)}

[0079] Where M is the mass matrix C is the damping matrix K is the stiffness matrix X is the displacement matrix {F(t)} is the excitation force

[0080] For a damped three-degree-of-freedom vibration system, the coordinate transformation of the differential equation modal matrix φ is:

[0081] M φ X″+C φ X′+K φ X=F φ

[0082] Where M φ is the modal mass matrix of the system, C φis the modal damping matrix, K φ is the modal stiffness matrix, M φ and K φ All are diagonal matrices. The damping matrix C obtained after coordinate transformation φ =φ T Cφ, becomes the modal damping matrix,

[0083] Diagonalization:

[0084]

[0085] The damping matrix is ​​a linear combination of the mass matrix and the stiffness matrix, namely:

[0086] C=αM+βK

[0087] Where α and β are coefficients.

[0088] It can be deduced that:

[0089]

[0090] The modal damping matrix is ​​a diagonal matrix and the damping is proportional damping.

[0091] The mass matrix, stiffness matrix, and damping matrix are diagonalized, and the equations are decoupled to obtain independent and uncoupled equations:

[0092]

[0093] In the formula, c pi is the i-th order modal damping coefficient, expressed as the damping ratio:

[0094]

[0095] Then we have:

[0096]

[0097] The solution for free vibration is:

[0098]

[0099] In the formula,

[0100] Transforming the response in the modal coordinates to the physical coordinates, the response of the system is:

[0101]

[0102] Then the main vibration mode of the system is:

[0103]

[0104] The vibration frequency of each vibration source is f = ω di / 2π. Adjust the structural parameters of the device shell so that its natural frequencies of each order are close to the vibration frequency of the vibration source. The flexible part of the device is deformed periodically under the action of the vibration source, squeezing the oil and causing the bubbles to float. The internal pressure of the device rises and falls periodically, so that the oil is continuously renewed and excess gas is discharged from the device.

[0105] As attached Figure 1 And attached Figure 2 As shown, the measuring device in this example is installed on the side wall of the oil pan 1 and fixed with bolts, the oil inlet 4 faces upward, the oil outlet 8 faces downward, and the exhaust pipe extends above the liquid surface of the oil pan 1 to ensure that the gas can be discharged smoothly. Two floats 10 and 12 are installed on the first exhaust pipe 9 and the second exhaust pipe 11, 30 mm away from the outlet. The two floats 10 and 12 rise and fall with the oil level in the oil pan 1. The outlets of the two exhaust pipes 9 and 11 are always located above the liquid level of the oil pan 1 to keep the gas outlet unobstructed. After the oil enters the measuring device from 4, it drips into 2 through the defoaming plate 13, the inclined plate 14 and the dropper 15. The oil increases, the internal pressure of 2 increases, the baffles 17 and 19 are pushed open, and the gas is discharged from the exhaust pipes 9 and 11; this design ensures smooth flow of oil and prevents oil from entering the measuring device. The exhaust pipes 9 and 11 need to extend to a height of 30 mm above the liquid level in the oil tank 1. The exhaust pipe outlets 26 and 27 are bent inward to prevent oil from splashing into the exhaust pipes. The diameter of the floats 10 and 12 is 20 mm and the thickness is 5 mm.

[0106] Figure 2 The detailed structure of the new oil sensor device and the functions of its components are shown. When the vehicle is stationary, the oil without foam flows into the oil inlet 4 of the device. The diameter of the oil inlet 4 is 20mm and the thickness is 4mm. The oil passes through the defoaming plate 13 to filter out large bubbles. The defoaming plate 13 has a diameter of 18mm and a thickness of 1mm. It is composed of a corrosion-resistant metal mesh. The inner circle of the metal mesh is small holes and the outer circle is large holes. The inner circle aperture is 2mm, the outer circle aperture is 3mm, and the transition area aperture is 2.4mm. Then, the remaining small bubbles rise and gather through the inclined plate 14. The inclined angle of the inclined plate 14 is 60° and the length is 5mm. Finally, it enters the dropper 15, which has an inner diameter of 5mm and a length of 16mm and is made of transparent polycarbonate material. The total height of the device is 150mm, the shell thickness is 2-4mm, the flexible material in the middle of the shell is polybenzimidazole (PBI), and the upper and lower parts of the shell are made of 316L steel.

[0107] As the oil gradually increases, the pressure in the middle layer 2 of the device increases, pushing open the baffle 17 and baffle 19 in the spring baffle, allowing the gas to be discharged from the first exhaust pipe 9 and the second exhaust pipe 11. The two baffles 17 and 19 are made of rigid material, with a diameter of 5mm and a thickness of 2mm. Springs 16 and 18 close 17 and 19. When the internal pressure increases, 17 and 19 pop open, and the gas is discharged through the first exhaust pipe 9 and the second exhaust pipe 11. After the pressure drops to the set pressure, 17 and 19 are closed by the spring. In this example, the exhaust pipe has an inner diameter of 5mm, a thickness of 2mm, and a length in the range of 100-150mm. It is made of corrosion-resistant material. The exhaust pipe outlet extends about 30mm above the liquid level of the oil pan 1, and is bent inward with a fine-pore baffle to prevent oil from splashing in. The oil pushes open the one-way valve core 25 and flows out from the outlet 8;

[0108] In the oil outlet 8 in this example, the diameter of the one-way valve core 25 is 16 mm and is made of corrosion-resistant material. The outer diameter of the device outlet is 20 mm, the inner diameter is 15 mm, the thickness is 2.5 mm, and it is made of 316L steel. In this process, the floats 10 and 12 float as the oil level in the oil tank 1 rises and falls, ensuring that the exhaust pipe is always located above the oil and the air outlet is kept unobstructed. The float has a diameter of 20 mm and a thickness of 5 mm and is made of solid buoyancy material. The entire process design ensures smooth oil flow, effective discharge of bubbles, and maintenance of pressure balance inside the measuring device.

[0109] In order to achieve the above purpose, this example includes multiple key components to ensure its functional integrity and measurement accuracy. The measuring device housing 2 is divided into three layers: the upper part 5 is made of 316L steel, 30mm high, 20mm top inlet diameter, 4mm wall thickness, which is the oil inlet area and bubble gathering area; the middle part 6 is 80mm high, 50mm inner diameter, 2mm thick, made of polybenzimidazole (PBI) material with specific elasticity, which deforms under the combined action of engine, vehicle speed change and oil damping effect, squeezes the internal space, and separates air and oil; the lower part 7 of the device is made of 316L steel, 40mm high, 20mm outlet diameter, 4mm wall thickness, and is equipped with a one-way valve 24 and a sensing element 3, wherein the one-way valve 24 ensures that the liquid can only flow outward to prevent backflow; the sensing element 3 is 30mm in diameter, 10mm thick, and the length of the three probes is 5-10mm, which can measure viscosity, temperature and density at the same time to improve measurement efficiency. Springs 16 and 18 and the baffle plate keep a stable amount of gas in the device. The spring baffle plate opens when the pressure reaches p0+ρg(h / 2), where p0 is the gas pressure in the oil pan and h is the height of the liquid level from the device inlet.

[0110] The pressure at the inlet of the device is p0+ρgh. The gas pressure inside the device is p0+ρg(h / 2) before deformation. After deformation, the internal pressure rises to (1.025~1.25)[p0+ρg(h / 2)], which is higher than the oil outlet pressure p0+ρg(h+0.15). Under the action of deformation, the outlet check valve is opened and the oil is discharged. Among them, p0>1.01325*10 5 Pa, ρ∈(840~860)kg / m 3

[0111] The following is a description of the important components and their specific functions:

[0112] The defoaming plate 13 is the primary defoaming structure of the measuring device, and its main function is to filter out large bubbles in the oil. When the oil flows in from 4, it first passes through the defoaming plate 13. Its special structural design can effectively intercept and break up large bubbles, preventing them from directly entering the measuring device, reducing the measurement deviation caused by the existence of bubbles, and ensuring that the sensor accurately detects the physical properties of the oil;

[0113] The inclined plate 14 optimizes the oil flow path, allowing small bubbles that are not filtered by the defoaming plate 13 to concentrate in the upper space, gradually gathering to form larger bubbles that rise to the top. The design of the inclined plate 14 makes it easier for bubbles to float up and be discharged, while guiding the oil to flow down smoothly, further improving the measurement accuracy of the device;

[0114] The dropper 15 is a narrow and flow-controlled pipe, which ensures that the oil flows slowly and steadily into 2, achieving the high-precision requirement of online real-time monitoring;

[0115] Exhaust pipes 9 and 11 are arranged on the upper side wall of the device for exhausting gas. The design ensures that the gas can be discharged smoothly without being blocked by oil. Exhaust pipes 9 and 11 extend to about 30 mm above the liquid level in the oil tank 1 and bend inward to prevent oil from splashing into the exhaust pipes;

[0116] Floats 10 and 12 are located in the oil tank 1 and float as the oil level in the oil tank rises and falls, ensuring that the exhaust pipe is always located above the oil to keep the air outlet unobstructed;

[0117] The baffles 17 and 19 maintain a certain pressure inside the device under the action of the springs 16 and 18, and maintain a certain amount of gas inside the device. When the defoaming gas gathers in 2 and the internal pressure increases, the baffles 17 and 19 are pushed open and the gas is discharged smoothly.

[0118] The one-way valve 24 is located at the outlet 8 to prevent backflow and the entry of external contaminants. The one-way valve 24 controls the one-way flow of oil to maintain the pressure balance inside and outside the device, ensure the stability of the measurement environment, improve the measurement accuracy and reliability of the device, reduce the maintenance frequency and cost, and ensure the efficiency and accuracy of oil quality measurement.

[0119] When in use, the device is filled with air before installation. After installation, the engine is not started, and oil without foam flows in from 4, passes through the defoaming plate 13, the inclined plate 14 and the dropper 15, and flows steadily into 2. The oil increases, and the internal pressure increases. When it reaches p0+ρg(h / 2), the one-way valves 17 and 19 are pushed open, and the air is discharged from 17 and 19, and the oil flows out through 8 until the device reaches a balanced state. p0 is the air pressure in the oil pan, and h is the height of the liquid level from the inlet of the device. At this time, the upper half of the device is filled with gas, and the lower half is filled with liquid. The oil quality sensing element 3 measures and outputs sensing signals such as density, viscosity and temperature.

[0120] When the engine starts and enters the running state, the foamed oil flows into the device, the oil flows in from 4, passes through the defoaming plate 13 to filter out large bubbles, and the inclined plate 14 makes the remaining small bubbles rise and gather, and then enters the dropper 15 and flows into 2. The flexible shell of the device vibrates and deforms under the combined action of vehicle vibration, engine vibration, road excitation and oil damping effect, squeezing the internal space of 2, causing the residual bubbles to float up, and the oil after two-stage defoaming flows to the sensing element. The sensing element 3 continuously measures the oil quality in a foam-free environment to achieve online real-time monitoring.

[0121] The oil quality measuring device of the present invention is particularly suitable for automobile engine oil pans and can provide high-precision and reliable measurement results in complex working environments. Compared with the prior art, the oil quality measuring device of the present invention is particularly suitable for automobile engine oil pans and can provide high-precision and reliable measurement results in complex working environments. Figure 7 As shown, the measurement precision and accuracy are significantly improved. The present invention relies on a multi-stage defoaming structure, in which the middle flexible component is deformed under the action of multiple vibration sources, squeezing the internal fluid, so that the residual bubbles are discharged upward through the air outlet, and the oil flows downward through the measurement sensing area; the device is provided with a self-protection valve plate to prevent the oil from entering the exhaust pipe, and a one-way valve is provided at the bottom of the device to prevent the backflow of oil with bubbles. The overall design is compact and easy to install, and can be easily integrated into the existing system architecture.

Claims

1. An engine oil pan oil quality measuring device, characterized in that: A shell is provided, which includes three parts: an upper part, a middle part and a lower part. The upper part and the lower part of the shell are both made of metal materials, the middle part of the shell is made of flexible materials, an oil inlet is provided on the top of the shell, a defoaming component is provided at the oil inlet, an air outlet is provided on the top side of the shell, a spring baffle is provided at the air outlet, the outside of the air outlet is connected to the exhaust pipe, an oil sensor is installed on the lower side wall of the shell, an oil outlet is provided at the bottom of the shell, a one-way valve for preventing oil backflow is provided at the oil outlet, the middle part of the shell made of flexible material is deformed and squeezed by the vibration of the oil to squeeze the fluid inside the shell, so that the bubbles float up, thereby realizing real-time and accurate monitoring of the lubricating oil status during vehicle operation.

2. The engine oil sump oil quality measuring device according to claim 1, characterized in that: Calculate the frequencies of each vibration source in the automobile system, determine the main vibration mode of the three-degree-of-freedom vibration system of the vehicle oil detection, and then adjust the shell structure parameters to make the natural frequencies of each order of the shell close to the vibration frequency of the vibration source. The first 6 natural frequencies of the middle flexible structure of the shell are 0.5Hz, 1.0Hz, 1.5Hz, 2Hz, 10Hz, and 20Hz. Calculate the vibration source frequency and determine the main vibration mode of the system as follows: Let m1 be the mass of the entire vehicle, spring stiffness k1 and damping c1; let the engine mass m2 be the suspension system, mounting bracket and other mechanical connections between m1 and spring stiffness k2 and damping c2; let the support structure, fixture and dynamic characteristics of the oil itself between the oil tank and oil mass m3 and the engine m2 be spring stiffness k3 and damping c3; let the coordinates x1, x2 and x3 of m1, m2 and m3 away from the static stable position, the forces on each mass block are F1(t), F2(t) and F3(t); let the coordinates x1, x2 and x3 of m1, m2 and m3 away from the static stable position, the forces on each mass block are F1(t), F2(t) and F3(t); The vibration differential equation of the vibration system in the x direction is as follows: For m1: m1x1″=-c1x1′+c2(x2′-x1′)-k1x1+k2(x2-x1)+F1(t)(1), For m2: m2x2″=-c2(x2′-x1′)+c3(x3′-x2′)-k2(x2-x1)+k3(x3-x2)+F2(t)(2), For m3: m3x3″=-c3(x3′-x2′)-k3(x3-x2)+F3(t)(3), The differential equation of the three-degree-of-freedom vibration system of vehicle oil detection is: In short: MX″+CX′+KX={F(t)}(8), Where M is the mass matrix C is the damping matrix K is the stiffness matrix X is the displacement matrix {F(t)} is the excitation force For a damped three-degree-of-freedom vibration system, the coordinate transformation of the differential equation modal matrix φ is: M φ X″+C φ X′+K φ X=F φ (9), Where M φ is the modal mass matrix of the system, C φ is the modal damping matrix, K φ is the modal stiffness matrix, M φ and K φ They are all diagonal matrices. The damping matrix C obtained after coordinate transformation is φ =φ T Cφ, becomes the modal damping matrix, After diagonalization, we get: The damping matrix is ​​a linear combination of the mass matrix and the stiffness matrix, namely: C=αM+βK(11), In the formula, α and β are coefficients; It can be deduced that: The above modal damping matrix is ​​a diagonal matrix, and the damping is proportional damping; The mass matrix, stiffness matrix, and damping matrix are diagonalized, and the equations are decoupled to obtain independent and uncoupled equations: In the formula, c pi is the i-th order modal damping coefficient, expressed as the damping ratio: Then we have: The solution for free vibration is: In the formula, Transforming the response in the modal coordinates to the physical coordinates, the response of the system is: Then the main vibration mode of the system is: The vibration frequency of each vibration source is f = ω di / 2π, adjust the structural parameters of the shell to make the natural frequencies of each order of the shell close to the vibration frequency of the vibration source.

3. The engine oil sump oil quality measuring device according to claim 1, characterized in that: The oil inlet is provided with a defoaming component which adopts a multi-stage defoaming component, including a defoaming plate and an inclined plate. When the oil flows in from the oil inlet on the top of the shell, it first passes through the defoaming plate, which is composed of a corrosion-resistant metal mesh. The inner circle of the metal mesh is small holes and the outer circle is large holes. After the oil flows through the defoaming plate, it passes through the inclined plate to make the remaining small bubbles rise and gather. The inclined plate is inclined on the side wall of the oil inlet and is arranged in a funnel shape. The lower end of the inclined plate is connected to the dropper and finally enters the dropper.

4. The engine oil sump oil quality measuring device according to claim 1, characterized in that: An air outlet is provided on the top side of the shell body, and the air outlet is arranged on the lower side of the oil inlet. The air outlet is connected to the first exhaust pipe. The air inlet end of the first exhaust pipe is provided with a spring baffle for closing / opening the first exhaust pipe. A second exhaust pipe is also provided. The lower end of the second exhaust pipe is connected to the defoaming component and is located at the oil inlet for timely discharging the gas filtered by the defoaming component. A spring baffle is also provided at the lower end of the second exhaust pipe. When the air pressure pushes open the spring baffle, the gas filtered by the defoaming component is discharged along the second exhaust pipe.

5. The engine oil sump oil quality measuring device according to claim 4, characterized in that: The exhaust pipe is made of corrosion-resistant material. The exhaust pipe outlet extends out of the oil pan liquid level and is bent inward with a fine-pore baffle to prevent oil from splashing in. Floats are respectively connected to the upper ends of the first exhaust pipe and the second exhaust pipe, so that they float with the rise and fall of the oil level in the oil tank through the floats, ensuring that the exhaust pipe is always above the oil.

6. The engine oil sump oil quality measuring device according to claim 1, characterized in that: The upper part of the shell is made of 316L steel, with a height of 30mm, a top inlet diameter of 20mm, and a wall thickness of 4mm. It is the oil inlet area and bubble gathering area; the middle part is 80mm high, 50mm inner diameter, and 2mm thick. It is made of elastic polybenzimidazole PBI material. It deforms under the combined action of the engine, vehicle speed changes, and oil damping effect, squeezing the internal space to separate the air and oil; the lower part of the shell is made of 316L steel, with a height of 40mm, a top inlet diameter of 20mm, and a wall thickness of 4mm. A one-way valve and an oil sensor are installed at the oil outlet. The one-way valve ensures that the liquid can only flow outward to prevent backflow.

7. A method for measuring the quality of oil in an engine oil pan, characterized in that: Using the engine oil pan oil quality measuring device as described in any one of claims 1 to 6, when the engine is not started, oil without foam flows in from the oil inlet, passes through the defoaming plate, the inclined plate and the dropper, and flows into the shell, the oil increases, and the bubbles are filtered out inside, resulting in an increase in gas pressure, and when the opening pressure of the spring baffle reaches p0+ρg(h / 2), where p0 is the gas pressure in the oil pan, and h is the height of the liquid level from the device inlet, the spring baffles at the air inlet ends of the first exhaust pipe and the second exhaust pipe are pushed open, and the gas is discharged from the first exhaust pipe and the second exhaust pipe, and the oil flows out through the oil outlet until the inside of the device reaches a state of equilibrium, at which time the upper half of the device is filled with gas and the lower half is filled with liquid, and the oil sensor measures and outputs density, viscosity and temperature; When the engine starts and enters the running state, foamy oil flows in from the oil inlet, passes through the defoaming plate to filter out large bubbles, and the inclined plate makes the remaining small bubbles rise and gather, and then enters the dropper and flows into the shell. The middle flexible shell of the shell vibrates and deforms under the combined action of vehicle vibration, engine vibration, road excitation and oil damping effect, squeezing the internal space of the shell and making the residual bubbles float up. The oil after two-stage defoaming flows to the oil sensor. The oil sensor continuously measures the oil quality in a foam-free environment to realize online real-time monitoring of density, viscosity and temperature.

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