Method for optimizing the oil return capacity of an engine

Abstract

The application discloses an optimization method of engine oil return capacity, comprising the following steps: S1, establishing an oil supply and return oil circuit simulation model, confirming the total oil supply flow and the oil supply flow of each oil supply oil channel under different working conditions of the engine; S2, judging whether the oil of each direction and each angle oil sump can completely immerse the oil suction disc inlet; if yes, executing S3; if no, executing S4; S3, judging whether the oil gas content of each direction and each angle oil suction disc inlet is less than the content threshold value; if yes, completing optimization; if no, executing S5; S4, judging whether the cylinder body, the cylinder cover and the oil sump have oil accumulation; if yes, executing S6 and then executing S2; if no, increasing the oil amount and executing S3; S5, judging whether the cylinder cover, the cylinder body and the oil sump have oil accumulation; if yes, executing S6 and then executing S3; if no, increasing the oil amount and completing optimization; and S6, optimizing the design of the oil return oil channel, the cavity and the oil sump. The application can save the test cost and shorten the test period.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of automobiles, and particularly relates to an optimization method for engine oil return capacity. BACKGROUND

[0002] The engine is placed on a special test bench, the engine oil filling amount is formulated according to experience, and the engine oil pressure and the oil gas content of the engine under different inclination directions and different inclination angles (the inclination directions include forward inclination, backward inclination, left inclination and right inclination, and the inclination angles include 20°, 25°, 30°, 35°, 40° and 45°) are tested to confirm the engine oil return capacity.

[0003] However, the above method has the following problems: 1. The test cost is high, the test period is long, and a large amount of test funds will be generated if multiple rounds of verification are performed; 2. In the extreme inclination angle test condition, the engine may fail and be damaged, which brings economic losses and test bench safety risks; 3. If the engine oil return capacity is identified through the test, the oil return channels of the cylinder body, the cylinder cover and other key parts will be redesigned, which will generate a large mold modification cost and seriously affect the project development period. SUMMARY

[0004] The purpose of the application is to place the engine on a special test bench, formulate the engine oil filling amount according to experience, test the engine oil return capacity under different inclination angles, and solve the problems of high test cost, long test period, and the possibility of engine failure and damage in the extreme inclination angle test condition. The application provides an optimization method for engine oil return capacity, which can fully evaluate the oil return capacity of the designed engine before the inclination test bench test, optimize the related design, reduce the number of tests at multiple inclination angles to shorten the test period, improve the one-time pass rate of the inclination test, reduce the development cost and the safety risk of the test bench test, and shorten the project development period.

[0005] To solve the above technical problems, the embodiment of the application discloses an optimization method for engine oil return capacity, which comprises the following steps:

[0006] S1: establishing an oil supply and return oil circuit simulation model of the engine, the oil supply and return oil circuit simulation model comprising a cylinder body, a cylinder cover, an oil pan, an oil supply channel, an oil return channel, a cavity, an oil suction disc and engine oil; and confirming the total oil supply flow of the engine under different working conditions and the oil supply flow of each oil supply channel through one-dimensional hydraulic dynamics simulation.

[0007] S2: According to the oil supply and return oil path simulation model and the total oil supply flow and the oil supply flow of each oil supply oil path under different working conditions of the engine, the dynamic return of the oil in the cylinder block, cylinder head and oil pan area under a plurality of directions and a plurality of inclination angles of a certain working condition of the base oil amount of the engine is simulated by three-dimensional fluid mechanics simulation; and it is judged whether the oil in the oil pan under each direction and each inclination angle can completely immerse the oil suction disc inlet;

[0008] If yes, step S3 is performed;

[0009] If no, step S4 is performed.

[0010] S3: The air content of the oil in the oil suction disc inlet area under each direction and each inclination angle is confirmed by three-dimensional fluid mechanics simulation, and it is judged whether the air content of the oil in the oil suction disc inlet area under each direction and each inclination angle is less than the content threshold value;

[0011] If yes, the optimization is completed;

[0012] If no, step S5 is performed.

[0013] S4: It is judged whether there is oil accumulation in the cylinder block, cylinder head and oil pan area;

[0014] If yes, step S6 is performed, and then step S2 is continued to be performed;

[0015] If no, step S7 is performed, and then step S3 is continued to be performed.

[0016] S5: It is judged whether there is oil accumulation in the cylinder head, cylinder block and oil pan area;

[0017] If yes, step S6 is performed, and then step S3 is continued to be performed;

[0018] If no, step S8 is performed, and the optimization is completed.

[0019] S6: The structure of the return oil path, cavity and oil pan that causes oil accumulation in the cylinder block, cylinder head and oil pan area is optimized and designed.

[0020] S7: The oil amount of the engine is increased to a first oil amount, so that the oil in the oil pan under each direction and each inclination angle can completely immerse the oil suction disc inlet.

[0021] S8: The oil amount of the engine is increased to a second oil amount, so that the air content of the oil in the oil suction disc inlet area under each direction and each inclination angle is less than the content threshold value.

[0022] By adopting the technical scheme, firstly, a simulation model of oil supply and return oil passage of engine oil is established, and the total oil supply flow of the engine oil and the oil supply flow of each oil supply passage under different working conditions of the engine are confirmed through one-dimensional hydraulic dynamics simulation, and then the dynamic return oil conditions of the cylinder block, the cylinder head and the oil pan area under a plurality of directions and a plurality of inclination angles of a certain working condition of the engine oil under a basic oil amount are simulated through three-dimensional fluid mechanics simulation. Then, whether the engine oil in the oil pan under each direction and each inclination angle can completely immerse the oil suction disc inlet is observed and judged more intuitively based on the simulation model, and then the air content of the engine oil in the oil suction disc inlet area under each direction and each inclination angle is confirmed through three-dimensional fluid mechanics simulation, and whether the air content of the engine oil in the oil suction disc inlet area under each direction and each inclination angle is less than the content threshold value is judged. If the engine oil in the oil pan under each direction and each inclination angle can completely immerse the oil suction disc inlet, and the air content of the engine oil in the oil suction disc inlet area under each direction and each inclination angle is less than the content threshold value, the optimization is completed.

[0023] If one of the conditions is not met, it is further judged whether there is engine oil accumulation in the cylinder head, the cylinder block and the oil pan area, if yes, the structure of the return oil passage, the cavity and the oil pan that causes the engine oil accumulation in the cylinder block, the cylinder head and the oil pan area is optimized, and if no, the engine oil amount of the engine is increased. In this way, at the engine part design stage, the engine return oil capacity under different directions and different inclination angles (especially under the limit inclination angle) of the engine can be identified in advance, if the return oil capacity is weak, the return oil passage, the cavity and the oil pan structure of the engine can be designed and optimized or a more reasonable engine oil amount of the engine can be determined, so that the return oil capacity of the designed engine can be fully evaluated before the inclined bench test, and relevant design optimization can be performed. The more reasonable engine oil amount of the engine can be increasing the engine oil amount to a first engine oil amount, so that the engine oil in the oil pan under each direction and each inclination angle can completely immerse the oil suction disc inlet, or increasing the engine oil amount to a second engine oil amount, so that the air content of the engine oil in the oil suction disc inlet area under each direction and each inclination angle is less than the content threshold value. In this way, the one-time pass rate of the bench inclined test can be greatly improved, the cost generated by repeated tests and the mold and tooling cost generated by the design change of related parts can be reduced, the development progress of the project can be effectively controlled, and the engine damage and the bench safety risk caused by the failure of the inclined test can be effectively avoided.

[0024] According to another specific embodiment of the application, the engine return oil capacity optimization method disclosed by the embodiments of the application, the basic engine oil amount is 4L-5L.

[0025] According to another specific embodiment of the application, the engine return oil capacity optimization method disclosed by the embodiments of the application, the plurality of directions include a front inclination direction, a rear inclination direction, a left inclination direction and a right inclination direction.

[0026] According to the technical scheme, the multiple directions include a front-inclination direction, a back-inclination direction, a left-inclination direction and a right-inclination direction, which can correspond to four working conditions of deceleration, acceleration, right turn and left turn of the vehicle respectively, and the four working conditions in the vehicle running process are simulated, so that the oil return capacity of the engine under the four working conditions can be determined more accurately.

[0027] According to another specific embodiment of the present application, the engine oil return capacity optimization method disclosed by the embodiment of the present application includes that the multiple inclination angles include inclination angles in an inclination angle range of 20°-45°.

[0028] According to the technical scheme, the oil return capacity of the engine under multiple inclination angles in the range of 20°-45° can be determined.

[0029] According to another specific embodiment of the present application, the engine oil return capacity optimization method disclosed by the embodiment of the present application includes that in the step S4 and the step S5, whether the oil accumulates in the cylinder block, the cylinder head and the oil pan area includes whether the oil accumulation in at least one area of the cylinder block, the cylinder head and the oil pan area is greater than an accumulation threshold.

[0030] According to the technical scheme, whether the oil accumulates in the cylinder block, the cylinder head and the oil pan area can be determined more accurately by judging whether the oil accumulation in at least one area of the cylinder block, the cylinder head and the oil pan area is greater than the accumulation threshold.

[0031] According to another specific embodiment of the present application, the engine oil return capacity optimization method disclosed by the embodiment of the present application includes that the accumulation threshold is 0.4L-0.6L.

[0032] According to another specific embodiment of the present application, the engine oil return capacity optimization method disclosed by the embodiment of the present application includes that the first oil amount is the minimum oil amount that can completely immerse the oil suction disc inlet in the oil pan under each inclination angle of each direction.

[0033] According to the technical scheme, the first oil amount is the minimum oil amount that can completely immerse the oil suction disc inlet in the oil pan under each inclination angle of each direction, which can avoid the phenomenon of excessive oil stirring, piston ring seizure, injection nozzle blockage and the like, and increase wear and reduce lubrication performance.

[0034] According to another specific embodiment of the present application, the engine oil return capacity optimization method disclosed by the embodiment of the present application includes that the second oil amount is the minimum oil amount that the gas content of the oil suction disc inlet area is less than a content threshold under each inclination angle of each direction.

[0035] According to the technical scheme, the second oil amount is the minimum oil amount in which the gas content of the oil in the suction disc inlet area is less than the content threshold value at each inclination in each direction, so that the phenomenon of excessive oil amount causing violent agitation, piston ring seizure, fuel nozzle blockage and the like can be avoided, and the wear and lubrication performance can be improved.

[0036] According to another specific embodiment of the present application, the method for optimizing the oil return capacity of an engine disclosed by the embodiments of the present application is provided, and the content threshold value is 13% to 17%.

[0037] According to another specific embodiment of the present application, the method for optimizing the oil return capacity of an engine disclosed by the embodiments of the present application is provided, and the step S6 includes at least one of expanding the cross-sectional area of the corresponding oil return gallery, increasing the inclination angle of the corresponding oil return gallery, reducing the step height in the cavity, and reducing the step height at the bottom of the oil pan.

[0038] According to the technical scheme, at least one of expanding the cross-sectional area of the corresponding oil return gallery, increasing the inclination angle of the corresponding oil return gallery, reducing the step height in the cavity, and reducing the step height at the bottom of the oil pan can improve the oil accumulation in the cylinder head, cylinder block and oil pan area, so as to optimize the oil return capacity of the engine.

[0039] The present application has the following advantages:

[0040] The present application provides a method for optimizing the oil return capacity of an engine. First, a simulation model of the oil supply and return circuit of the engine is established, and the total oil supply flow and the oil supply flow of each oil supply gallery under different working conditions of the engine are confirmed through one-dimensional hydraulic dynamics simulation. Then, the dynamic oil return of the cylinder block, cylinder head and oil pan area under a certain working condition of multiple directions and multiple inclinations of the oil amount of the engine is simulated through three-dimensional fluid mechanics simulation. Then, based on the simulation model, it is more intuitive to observe and judge whether the oil in the oil pan under each inclination in each direction can completely immerse the suction disc inlet. Then, the gas content of the oil in the suction disc inlet area under each inclination in each direction is confirmed through three-dimensional fluid mechanics simulation, and it is judged whether the gas content of the oil in the suction disc inlet area under each inclination in each direction is less than the content threshold value. If the oil in the oil pan under each inclination in each direction can completely immerse the suction disc inlet and the gas content of the oil in the suction disc inlet area under each inclination in each direction is less than the content threshold value, the optimization is completed.

[0041] If one of the conditions is not met, it is necessary to further determine whether there is oil accumulation in the cylinder head, cylinder block and oil pan area, if yes, the structure of the oil return oil passage, cavity and oil pan that causes oil accumulation in the cylinder block, cylinder head and oil pan area needs to be optimized; if no, the oil amount of the engine is increased. In this way, at the engine part design stage, the engine oil return capacity in different directions and different inclination angles (especially in the limit inclination angle) can be identified in advance, if the oil return capacity is weak, the structure of the oil return oil passage, cavity and oil pan of the engine can be optimized or a more reasonable oil amount of the engine is determined, so that the oil return capacity of the engine can be optimized before the inclination test. The more reasonable oil amount of the engine can be that the oil amount of the engine is increased to the first oil amount, so that the oil in the oil pan in each direction and each inclination angle can completely immerse the oil suction disc inlet, or the oil amount of the engine is increased to the second oil amount, so that the oil gas content in the oil suction disc inlet area in each direction and each inclination angle is less than the content threshold. In this way, the one-time pass rate of the bench inclination test can be greatly improved, the cost generated by repeated tests and the mold and tooling cost generated by the design change of related parts can be reduced, the development progress of the project can be effectively controlled, and the engine damage and bench safety risk caused by the failure of the inclination test can be effectively avoided. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 Flow chart of the engine oil return capacity optimization method of the embodiment of the present application;

[0043] Figure 2 Structure schematic diagram of the engine oil supply and return oil path simulation model of the engine oil return capacity optimization method of the embodiment of the present application;

[0044] Figure 3 Schematic diagram of different oil amounts and oil suction disc inlet immersion depths of the engine in a same inclination angle under static working condition, acceleration working condition, deceleration working condition, left turning working condition and right turning working condition;

[0045] Figure 4 Schematic diagram of four existence modes of oil gas bubbles in oil liquid;

[0046] Figure 5 Structure schematic diagram of four oil return passages of the cylinder head of the engine;

[0047] Figure 6 Before optimization Figure 5 Cross-sectional view of A-A position;

[0048] Figure 7 After optimization Figure 5 Cross-sectional view of A-A position;

[0049] Figure 8 Structure diagram of an oil pan before optimization;

[0050] Figure 9 Structure diagram of an oil pan after optimization.

[0051] Explanation of reference numerals:

[0052] 100: cylinder block; 200: cylinder head; 300: oil pan; 400: oil supply passage; 500: oil return passage; 600: cavity; 700: oil suction plate; 800: exhaust side oil return passage opening; 900: middle oil return passage opening. DETAILED DESCRIPTION

[0053] The present application is described in greater detail by the specific working examples below, from which those skilled in the art will readily derive other advantages and embodiments of the present application. Although the present application will be described with reference to the preferred embodiments, it will be understood that the application is not limited to the details of the embodiments. Rather, the embodiments are provided to cover the application as it extends to alternatives or modifications that are obvious to those skilled in the art. In order to provide a thorough understanding of the present application, numerous specific details are described in the following description. The present application can be practiced without these details. In addition, well-known elements have not been described in detail in order to avoid obscuring the present application. It should be noted that, in the following description, like reference numerals and letters refer to like elements throughout the several views of the drawings, and thus, once an element is defined in one drawing, it is not necessary to further define and explain it in the subsequent drawings.

[0054] It should be noted that, in the present specification, like reference numerals and letters represent like items in the following drawings, and thus, once an item is defined in one drawing, it is not necessary to further define and explain it in the subsequent drawings.

[0055] In the description of the present embodiments, it should be noted that the terms "upper", "lower", "inner", "bottom", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present application is usually placed, and are merely for the convenience of describing the present application and simplifying the description, and thus, cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, cannot be understood as limiting the present application.

[0056] The terms "first", "second", etc. are merely used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0057] In the description of the embodiments, it should also be noted that unless specifically defined and limited, the terms "set", "connected", "connection" should be understood broadly, for example, can be fixedly connected, can also be detachably connected, or integrally connected; can be mechanically connected, can also be electrically connected; can be directly connected, can also be indirectly connected through an intermediate medium, and can be internal communication of two elements. For those skilled in the art, the specific meanings of the above terms in the embodiments can be understood according to the specific circumstances.

[0058] In order to make the purpose, technical scheme and advantages of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0059] The embodiments of the present application disclose a method for optimizing the oil return capacity of an engine, as shown in the formula (I), comprising the following steps: Figure 1

[0060] S1: establishing an oil supply and return oil circuit simulation model of the engine oil, as shown in the formula (II), the oil supply and return oil circuit simulation model comprises a cylinder body 100, a cylinder head 200, an oil pan 300, an oil supply channel 400, an oil return channel 500, a cavity 600, an oil suction disc 700 and engine oil. And the total oil supply flow of the engine oil and the oil supply flow of each oil supply channel under different working conditions of the engine are confirmed by one-dimensional hydraulic dynamics simulation. Figure 2

[0061] It should be noted that in the embodiments, the oil supply and return oil circuit simulation model of the engine oil as shown in the formula (II) can be established by using the computational fluid software StarCCM+. Figure 2 In the oil supply and return oil circuit simulation model, the engine oil can use a gas-liquid two-phase flow fluid according to its physical properties, the two-phase flow fluid contains engine oil and air, the density and viscosity of the two can be input respectively, and the volume ratio of the engine oil and air is calculated by establishing an equation with the volume ratio as an unknown quantity.

[0062] In the embodiments, one-dimensional hydraulic dynamics simulation software AMESIM can be used to model and confirm the total oil supply flow of the engine oil and the oil supply flow of each oil supply channel under different working conditions of the engine. The one-dimensional hydraulic dynamics model is to solve the pressure, flow rate value, etc. of each oil supply channel by establishing an equation group based on the mass, momentum transport and conservation relationship of the engine oil. The input information for establishing the mode is the pump displacement-resistance curve, pipeline flow resistance and other fluid mechanics information. The different working conditions of the engine include full load or partial load working conditions under multiple different speeds, and the multiple different speed ranges include 1000r / min-4500r / min.

[0063] ​​S2: According to the oil supply and return oil path simulation model and the total oil supply flow and the oil supply flow of each oil supply oil path under different working conditions of the engine, the dynamic return of the oil in the cylinder block, the cylinder head and the oil pan under a certain working condition of the engine with the oil amount being the basic oil amount and a plurality of directions and a plurality of inclination angles is simulated by three-dimensional fluid mechanics simulation; and it is judged whether the oil in the oil pan under each direction and each inclination angle can completely immerse the oil suction disc inlet; if yes, step S3 is executed; if no, step S4 is executed.

[0064] It should be noted that in the embodiment, the dynamic return of the oil in the cylinder block, the cylinder head and the oil pan under a certain working condition of the engine with the oil amount being the basic oil amount and a plurality of directions and a plurality of inclination angles can be simulated by the three-dimensional computational fluid dynamics software StarCCM+. The engine oil supply process is that the oil pump sucks the oil in the oil pan into the main oil supply oil path of the cylinder block, and distributes the oil to each bearing of the engine through the oil supply oil paths of each branch of the main oil supply oil path to implement lubrication or cooling. Therefore, the oil in the oil pan needs to completely immerse the oil suction disc inlet to ensure the normal operation of the engine. The dynamic return process is that the oil accumulated in the low-pressure oil cavity below the camshaft cover flows downward to the oil pan through the oil return oil path inside the cylinder block and the cylinder head. Therefore, a high oil return rate is needed to make the oil reach the oil pan in time to avoid the oil pump from not sucking oil or sucking oil with too high gas content. In general, in the embodiment, the certain working condition can be selected as the working condition of full load and 4000 r / min of the engine.

[0065] In the embodiment, the basic oil amount is determined according to the oil in the oil pan of the engine under the static working condition (static) which can completely immerse the oil suction disc inlet and an additional design allowance. In general, the design allowance is 0.25 L. In one specific embodiment, the basic oil amount is 4 L to 5 L.

[0066] In one specific embodiment, the plurality of directions includes a front inclination direction, a rear inclination direction, a left inclination direction and a right inclination direction, which respectively simulate four working conditions of vehicle deceleration, acceleration, right turn and left turn.

[0067] In one specific embodiment, the plurality of inclination angles includes inclination angles in the range of 20° to 45°, and the specific inclination angles can be 20°, 25°, 30°, 35°, 40°, 45° and the like, and can also be other inclination angles in the range of 20° to 45°. In the embodiment, the larger the inclination angle, the worse the oil return ability of the engine under the same direction, and in the simulation process, a plurality of inclination angles can be selected for simulation, or an inclination angle with a large inclination angle can be selected for simulation, for example, 35°.

[0068] Figure 3Fig. 1 shows the schematic diagram of the oil amount and the depth of the oil suction plate inlet submerged in different conditions of the engine at the same inclination angle, including the static condition, the acceleration condition, the deceleration condition, the left turning condition and the right turning condition. Figure 3 As shown in Fig. 1, the greater the oil amount, the deeper the depth of the oil suction plate inlet submerged in the same condition of the engine. For example, when the oil amount is 1.5L, the depth of the oil suction plate inlet submerged is about 20mm in the deceleration (forward inclination) condition of the engine; when the oil amount is 2.5L, the depth of the oil suction plate inlet submerged is about 45mm; when the oil amount is 3.5L, the depth of the oil suction plate inlet submerged is about 63mm. Figure 3 As shown in Fig. 2, when the depth of the oil suction plate inlet submerged is the same, the least oil amount is needed in the static condition of the engine, and the greatest oil amount is needed in the acceleration (backward inclination) condition of the engine. For example, when the depth of the oil suction plate inlet submerged is 20mm, the oil amount needed in the static condition of the engine is about 0.75L, the oil amount needed in the deceleration (forward inclination) condition of the engine is about 1.5L, the oil amount needed in the right turning (left inclination) condition of the engine is about 2.75L, the oil amount needed in the left turning (right inclination) condition of the engine is about 3.6L, and the oil amount needed in the acceleration (backward inclination) condition of the engine is about 3.9L.

[0069] S3: confirming the gas content of the oil in the oil suction plate inlet area at each inclination angle in each direction by three-dimensional fluid mechanics simulation, and judging whether the gas content of the oil in the oil suction plate inlet area at each inclination angle in each direction is less than the content threshold value; if yes, the optimization is completed; if no, step S5 is performed.

[0070] In one specific embodiment, the content threshold value is 13% to 17%. Specifically, the content threshold value can be 13%, 14%, 15%, 16% or 17%, which can be set by a person skilled in the art according to the actual situation.

[0071] It should be noted that in the present embodiment, the gas content of the oil in the oil suction plate inlet area at each inclination angle in each direction can be simulated and confirmed by using the Euler multiphase flow (EMP) and the free surface (VOF) model in the computational fluid software StarCCM+. The physical property parameters of the oil and air are input in the EMP model, and the proportion of the two substances in the oil-air intersection area can be calculated. The initial liquid surface position is input in the VOF model, and the boundary surface between the oil flow and the external air can be calculated. Figure 4 Fig. 3 shows the schematic diagram of the four existing modes of the oil bubbles in the oil liquid. Figure 4As shown, further can be calculated by establishing the mass transfer equation of the gas phase components of the oil gas bubble in the oil return gallery, (low pressure) oil cavity, oil sump, the formation, combination and crushing process, ultimately determine the oil gas content of the oil pan inlet area under each direction of each angle. If the oil gas content of the oil pan inlet area is greater than the content threshold, it will cause the oil to be unable to effectively contact the friction parts such as bearings, bushings, etc. in the bearing and other parts, resulting in insufficient lubrication.

[0072] S4: determine whether there is oil accumulation in the cylinder block, cylinder head and oil pan area; if yes, execute step S6, and then continue to execute step S2; if no, execute step S7, and then continue to execute step S3. S6: optimize the design of the structure of the oil return gallery, cavity and oil pan that causes oil accumulation in the cylinder block, cylinder head and oil pan area. S7: increase the oil amount of the engine to the first oil amount, so that the oil in the oil pan under each direction of each angle can completely immerse the oil pan inlet.

[0073] In a specific embodiment, determining whether there is oil accumulation in the cylinder block, cylinder head and oil pan area includes determining whether the amount of oil accumulation in at least one area of the cylinder block, cylinder head and oil pan area is greater than the accumulation amount threshold. In a specific embodiment, the accumulation amount threshold is 0.4L-0.6L.

[0074] In a specific embodiment, the first oil amount is the minimum oil amount that can completely immerse the oil pan inlet in the oil pan under each direction of each angle, which can avoid the situation that excessive oil amount causes severe stirring phenomenon, piston ring seizure, fuel injector blockage and other faults, and increases wear and reduces lubrication performance.

[0075] S5: determine whether there is oil accumulation in the cylinder head, cylinder block and oil pan area; if yes, execute step S6, i.e. optimize the design of the structure of the oil return gallery, cavity and oil pan that causes oil accumulation in the cylinder block, cylinder head and oil pan area, and then continue to execute step S3; if no, execute step S8, and complete optimization. S8: increase the oil amount of the engine to the second oil amount, so that the oil gas content of the oil pan inlet area under each direction of each angle is less than the content threshold.

[0076] In a specific embodiment, the second oil amount is the minimum oil amount that can completely immerse the oil pan inlet area under each direction of each angle, which can avoid the situation that excessive oil amount causes severe stirring phenomenon, piston ring seizure, fuel injector blockage and other faults, and increases wear and reduces lubrication performance.

[0077] The above technical solution first establishes a simulation model of the engine oil supply and return circuit. One-dimensional hydraulic dynamics simulation is used to confirm the total oil supply flow rate and the oil supply flow rate of each oil supply passage under different engine operating conditions. Then, three-dimensional fluid dynamics simulation is used to simulate the dynamic oil return situation in the cylinder block, cylinder head, and oil pan regions under multiple tilt angles in multiple directions under a certain operating condition, based on the engine oil quantity. Next, based on the simulation model, it is more intuitively observed and judged whether the oil in the oil pan at each tilt angle in each direction can completely submerge the oil suction plate inlet. Then, three-dimensional fluid dynamics simulation is used to confirm the gas content of the oil in the oil suction plate inlet region at each tilt angle in each direction, and to determine whether the gas content of the oil in the oil suction plate inlet region at each tilt angle in each direction is less than the content threshold. If the oil in the oil pan at each tilt angle in each direction can completely submerge the oil suction plate inlet and the gas content of the oil in the oil suction plate inlet region at each tilt angle in each direction is less than the content threshold, then the optimization is complete.

[0078] If any one of the conditions is not met, it is necessary to further determine whether there is oil accumulation in the cylinder head, cylinder block, and oil pan areas. If so, the structure of the oil return passages, chambers, and oil pan that cause oil accumulation in these areas needs to be optimized. If not, the engine oil volume needs to be increased. This allows for early identification of the engine's oil return capability at different tilt angles (especially at extreme tilt angles) during the engine component design phase. If the oil return capability is weak, the design of the engine's oil return passages, chambers, and oil pan structure can be optimized, or a more reasonable engine oil volume can be determined. A more reasonable engine oil volume could specifically be increased to a first oil volume to ensure that the oil in the oil pan at all tilt angles in all directions completely submerges the oil suction plate inlet, or increased to a second oil volume to ensure that the oil gas content in the oil suction plate inlet area at all tilt angles in all directions is less than the content threshold. This can significantly improve the first-pass yield of the bench tilt test, reduce the costs of repeated tests and the mold and tooling costs caused by changes in the design of related parts, effectively control the development progress of the project, and effectively avoid engine damage and bench safety risks caused by failure of the tilt test.

[0079] In one specific embodiment, step S6 involves optimizing the structure of the return oil passage, cavity, and oil pan that cause oil accumulation in the cylinder block, cylinder head, and oil pan areas, including at least one of: increasing the cross-sectional area of ​​the corresponding return oil passage, increasing the inclination angle of the corresponding return oil passage, reducing the step height in the cavity, and reducing the step height at the bottom of the oil pan.

[0080] It should be noted that in the present embodiment, if oil accumulates in the cylinder block, the cylinder head region, at least one of the following measures can be taken to avoid oil accumulation: increasing the cross-sectional area of the corresponding oil return gallery, increasing the inclination angle of the corresponding oil return gallery, and reducing the step height in the cavity (particularly the low-pressure oil cavity). If oil accumulates in the oil pan region, reducing the step height at the bottom of the oil pan can avoid oil accumulation.

[0081] Figure 5 A schematic view of the structure of four oil return galleries of the cylinder head of an engine, Figure 6 A schematic view of the structure of four oil return galleries of the cylinder head of an engine, Figure 5 A cross-sectional view of the A-A position (the position of the oil return gallery that causes oil accumulation in the cylinder head of an engine) before optimization, Figure 7 A cross-sectional view of the A-A position (the position of the oil return gallery that causes oil accumulation in the cylinder head of an engine) before optimization, Figure 5 A cross-sectional view of the A-A position after optimization. As shown in Figure 5 , each of the four exhaust-side oil return passage openings 800 and the corresponding four middle oil return passage openings 900 communicates to form an oil return gallery. As shown in Figure 6 and Figure 7 , in order to avoid oil accumulation in the cylinder head, the cross-sectional area (diameter) of the oil return gallery (i.e., the oil gallery formed between the exhaust-side oil return passage opening 800 and the corresponding middle oil return passage opening 900) that causes oil accumulation in the cylinder head is increased. Specifically, as shown in Figure 6 , the diameter of the oil return gallery formed between the exhaust-side oil return passage opening 800 and the corresponding middle oil return passage opening 900 at a certain position before optimization is about 10 mm. As shown in Figure 7 , the diameter of the oil return gallery formed between the exhaust-side oil return passage opening 800 and the corresponding middle oil return passage opening 900 at the same position after optimization is about 20 mm, i.e., an increase of 1 times.

[0082] Figure 8 A schematic view of the structure of the oil pan of an engine before optimization, Figure 9 A schematic view of the structure of the oil pan of an engine after optimization. As shown in Figure 8 and Figure 9 , the black part represents oil, and the oil in the oil pan 300 before optimization does not submerge the inlet of the oil suction disc 700. By reducing the step height at the bottom of the oil pan 300, the oil in the oil pan 300 can submerge the inlet of the oil suction disc 700.

[0083] By at least one of the following measures: increasing the cross-sectional area of the corresponding oil return gallery, increasing the inclination angle of the corresponding oil return gallery, reducing the step height in the cavity, and reducing the step height at the bottom of the oil pan, the accumulation of oil in the cylinder head, cylinder block, and oil pan regions can be improved, thereby optimizing the oil return capacity of the engine.

[0084] While the application has been illustrated and described in connection with certain preferred embodiments thereof, it will be readily apparent to those of ordinary skill in the art that various changes in form and detail can be made therein without departing from the spirit and scope of the application. It is intended to encompass all such changes and alterations in the details thereof.

Claims

1. A method of optimizing engine oil return capability, characterized by, The method comprises the following steps: S1: establishing an oil supply and return oil passage simulation model of engine oil, the oil supply and return oil passage simulation model comprising a cylinder block, a cylinder head, an oil pan, an oil supply oil passage, an oil return oil passage, a cavity, an oil suction disc and engine oil; and confirming the total oil supply flow of the engine oil and the oil supply flow of each oil supply oil passage under different working conditions of the engine through one-dimensional hydraulic dynamics simulation; S2: simulating, according to the oil supply and return oil passage simulation model and the total oil supply flow of the engine oil and the oil supply flow of each oil supply oil passage under different working conditions of the engine, the dynamic oil return of the cylinder block, the cylinder head and the oil pan area under a plurality of directions and a plurality of inclination angles of a certain working condition of the engine oil amount being a basic engine oil amount through three-dimensional fluid mechanics simulation; and judging whether the engine oil in the oil pan can completely immerse the oil suction disc inlet under each direction and each inclination angle; if yes, performing step S3; if no, performing step S4; S3: confirming the air content of the oil suction disc inlet area under each direction and each inclination angle through three-dimensional fluid mechanics simulation, and judging whether the air content of the oil suction disc inlet area under each direction and each inclination angle is less than a content threshold value; if yes, completing optimization; if no, performing step S5; S4: judging whether there is engine oil accumulation in the cylinder block, the cylinder head and the oil pan area; if yes, performing step S6, and then continuing to perform the step S2; if no, performing step S7, and then continuing to perform the step S3; S5: judging whether there is engine oil accumulation in the cylinder head, the cylinder block and the oil pan area; if yes, performing step S6, and then continuing to perform the step S3; if no, performing step S8, and completing optimization; S6: optimizing the structure of the oil return oil passage, the cavity and the oil pan which causes engine oil accumulation in the cylinder block, the cylinder head and the oil pan area; S7: increasing the engine oil amount of the engine to a first engine oil amount, so that the engine oil in the oil pan under each direction and each inclination angle can completely immerse the oil suction disc inlet; S8: increasing the engine oil amount of the engine to a second engine oil amount, so that the air content of the oil suction disc inlet area under each direction and each inclination angle is less than the content threshold value.

2. The method of optimizing engine oil return capability of claim 1, wherein, In the step S2, the basic engine oil amount is 4L-5L.

3. The method of optimizing engine oil return capability of claim 1, wherein, The plurality of directions comprises a front inclination direction, a rear inclination direction, a left inclination direction and a right inclination direction.

4. The method of optimizing engine oil return capability of claim 3, wherein, The plurality of inclination angles comprises an inclination angle in an inclination angle range of 20°-45°.

5. The method of optimizing engine oil return capability of claim 1, wherein, In the step S4 and the step S5, judging whether there is engine oil accumulation in the cylinder block, the cylinder head and the oil pan area comprises judging whether the engine oil accumulation amount in at least one area of the cylinder block, the cylinder head and the oil pan area is greater than an accumulation amount threshold value.

6. The method of optimizing engine oil return capability of claim 5, wherein, The accumulation amount threshold value is 0.4L-0.6L.

7. The method of optimizing engine oil return capability of claim 1, wherein, The first engine oil amount is the minimum oil amount under which the engine oil in the oil pan under each direction and each inclination angle can completely immerse the oil suction disc inlet.

8. The method of optimizing engine oil return capability of claim 1, wherein, The second oil amount is a minimum oil amount in which the gas content of the oil in the inlet area of the oil pan is less than the content threshold value at each inclination angle in each direction.

9. The method of optimizing engine oil return capability of claim 8, wherein, The content threshold value is 13% to 17%.

10. The method of optimizing the oil return capability of an engine according to any one of claims 1 to 9, characterized in that, In the step S6, the structure of the oil return passage, the cavity and the oil pan that causes the oil to accumulate in the cylinder block, the cylinder head and the oil pan area is optimized by at least one of enlarging the cross-sectional area of the corresponding oil return passage, increasing the inclination angle of the corresponding oil return passage, reducing the step height in the cavity, and reducing the step height at the bottom of the oil pan.

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