Oil way system, design method and engine

Abstract

The invention provides an oil way system, a design method and an engine. The oil way system comprises an oil pump; the cooler is provided with an oil inlet hole and an oil outlet hole, and the oil outlet hole is communicated with the main oil way; the first pipeline is communicated with the second pipeline, the first pipeline is connected with an oil pump outlet of the oil pump, and the second pipeline is communicated with the oil inlet hole; wherein an included angle is formed between the extension direction of the first pipeline and the extension direction of the second pipeline. According to the system, through the curve oil way design between the engine oil pump and the cooler, fluid pressure loss is increased, pulse excitation is reduced, and the purpose of improving the NVH performance of an engine is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the engine technical field, and more particularly, to an oil circuit system, a design method and an engine in the engine technical field. BACKGROUND

[0002] The vibration noise level of an engine oil pump is one of the important evaluation indexes of the comprehensive performance of the engine. With the globalization of the market, more methods are proposed to reduce the vibration noise of the oil pump, improve the NVH (Noise Vibration Harshness) quality of the engine, improve the vibration noise quality of the engine, and also an important way to reduce the noise in the vehicle cab.

[0003] In the related art, the application of the balance shaft is cancelled in the self-suction project of the engine, so that the background noise of the whole machine is reduced. However, the reduction of the background noise of the whole machine makes the engine oil circuit radiation noise more prominent, and reduces the user experience. SUMMARY

[0004] The present application provides an oil circuit system, a design method and an engine. The system increases fluid pressure loss and reduces pulse excitation through the design of the bend between the oil pump and the cooler, so as to achieve the purpose of improving the NVH performance of the engine.

[0005] In a first aspect, an oil circuit system is provided, comprising: an oil pump; a cooler, the cooler having an oil inlet hole and an oil outlet hole, the oil outlet hole being in communication with a main oil circuit; a first pipeline and a second pipeline, the first pipeline and the second pipeline being in communication, the first pipeline being connected to an oil pump outlet of the oil pump, and the second pipeline being in communication with the oil inlet hole; wherein the extension direction of the first pipeline and the extension direction of the second pipeline have an included angle.

[0006] The oil circuit system of the present application embodiment increases fluid pressure loss and reduces pulse excitation through the design of the included angle between the extension direction of the first pipeline and the extension direction of the second pipeline, so as to achieve the purpose of reducing the engine radiation noise and improving the NVH performance of the engine.

[0007] In combination with the first aspect, in some possible implementation manners, the included angle is 90°-160°.

[0008] In combination with the first aspect and the above implementation manner, in some possible implementation manners, the oil circuit system further comprises: a buffer member, the buffer member being arranged upstream of the oil inlet hole of the cooler and being connected to the second pipeline.

[0009] With reference to the first aspect and the above implementation manners, in some possible implementation manners, the buffer member includes a buffer cavity, opposite two side walls of the buffer cavity are respectively provided with a buffer inlet and a buffer outlet, the buffer inlet is connected with the second pipeline, the buffer outlet is in communication with the oil inlet hole, and a flow passage diameter of the buffer outlet is smaller than a flow passage diameter of the buffer inlet.

[0010] Through the above technical solution, the diameters of the buffer outlet and the buffer inlet are designed to achieve the effect of attenuating high-frequency pulses.

[0011] In a second aspect, a design method of an oil circuit system is provided, the method including: constructing an oil circuit connection model of the oil circuit system; obtaining an initial engine oil pressure amplitude of the oil circuit connection model, calculating an amplitude difference between the initial engine oil pressure amplitude and a preset pressure amplitude; adjusting an included angle based on the amplitude difference until an oil pan noise of the oil circuit connection model meets a preset noise attenuation condition, and generating at least one design parameter of the oil circuit.

[0012] The design method of the oil circuit system according to the embodiments of the present application first constructs an oil circuit connection model of the oil circuit system, obtains an initial engine oil pressure amplitude of the oil circuit connection model, calculates an amplitude difference between the initial engine oil pressure amplitude and a preset pressure amplitude, then adjusts an included angle based on the amplitude difference until an oil pan noise of the oil circuit connection model meets a preset noise attenuation condition, and generates at least one design parameter of the oil circuit. Thus, the method increases fluid pressure loss through the design of the bend between the oil pump and the cooler, reduces pulse excitation, and effectively reduces engine radiation noise by adjusting the bend included angle based on the amplitude difference, thereby achieving the purpose of improving engine NVH performance.

[0013] With reference to the second aspect, in some possible implementation manners, in the case that the oil circuit system further includes a buffer member, adjusting the included angle based on the amplitude difference until the oil pan noise of the oil circuit connection model meets the preset noise attenuation condition includes: determining an angle adjustment range according to the amplitude difference; matching the angle adjustment range based on a target design parameter of the oil circuit system to obtain a target angle, and adjusting the included angle according to the target angle; when the oil pan noise of the oil circuit connection model does not meet the preset noise attenuation condition, adjusting a cavity volume of the buffer member according to the engine oil pressure amplitude and the initial engine oil pressure amplitude of the oil circuit connection model until the oil pan noise meets the preset noise attenuation condition.

[0014] By the technical solution, the optimal angle value is determined from the angle adjustment range determined according to the amplitude difference in combination with other design parameters of the oil circuit system, the included angle between the first pipeline and the second pipeline is adjusted, so as to reduce the fluid pressure pulsation amplitude, the peak pressure fluctuation of the low-frequency pulse can be effectively reduced through the included angle adjustment, and then the noise generated by the fluid pulsation excitation is reduced, so that the purpose of optimizing the engine NVH performance is achieved. Then, in the case that the oil circuit connection model after the included angle adjustment meets the preset noise attenuation condition, the design is frozen, and the design parameters of the oil circuit are determined; if the preset noise attenuation condition is not met, then the cavity volume of the buffer is adjusted, and the peak pressure fluctuation of the high-frequency pulse can be effectively reduced through the cavity volume adjustment. Therefore, through the cyclic adjustment sequence of the included angle adjustment and the cavity volume adjustment, the balanced optimization effect of the pressure fluctuation is achieved.

[0015] In combination with the second aspect and the above implementation manners, in some possible implementation manners, the angle adjustment range is determined according to the amplitude difference, including: obtaining an initial angle of the included angle, and determining a maximum allowed adjustment angle according to the initial angle; obtaining a preset engine oil viscosity and a preset engine oil flow rate of the oil circuit system, and determining a correction angle according to the amplitude difference, the preset engine oil viscosity and the preset engine oil flow rate; and correcting the maximum allowed adjustment angle according to the correction angle to determine the angle adjustment range.

[0016] Through the technical solution, the maximum allowed adjustment angle allowed by the oil circuit design can be first determined according to the initial angle, and then the maximum allowed adjustment angle is adjusted in combination with the amplitude difference between the initial engine oil pressure amplitude and the preset pressure amplitude in the case that the oil circuit design is allowed, so as to obtain the angle adjustment range that meets the requirements of the oil circuit design and satisfies the pressure amplitude adjustment.

[0017] In combination with the second aspect and the above implementation manners, in some possible implementation manners, the cavity volume of the buffer is adjusted according to the engine oil pressure amplitude of the oil circuit connection model, including: obtaining an actual amplitude difference between the engine oil pressure amplitude of the oil circuit connection model and a preset pressure amplitude; determining a target cavity cross-sectional area based on the actual amplitude difference and a current cavity cross-sectional area of the buffer, so as to adjust the cavity volume of the buffer according to the target cavity cross-sectional area.

[0018] Through the technical solution, the target cavity cross-sectional area of the buffer can be determined according to the actual amplitude difference between the engine oil pressure amplitude of the oil circuit connection model after the included angle adjustment and the preset pressure amplitude, so as to obtain the cavity volume of the buffer that meets the pressure pulse attenuation requirement, and the parameter adjustment precision of the buffer is improved.

[0019] With reference to the second aspect and the above implementation manners, in some possible implementation manners, the design method of the oil circuit system further includes: extracting a fluid flow region of the oil circuit connection model to construct a corresponding flow channel model; performing fluid dynamics calculation on the flow channel model based on a preset boundary condition to obtain a pressure fluctuation excitation force; identifying a corresponding engine oil pressure amplitude based on the pressure fluctuation excitation force and the target monitoring position; and mapping the pressure fluctuation excitation force to an acoustic grid corresponding to the flow channel model to obtain corresponding oil sump noise.

[0020] By the above technical solution, through the multi-physics field simulation technology, the entire physical process from the excitation generated by the oil pump, to the transmission and modulation through the oil circuit, and finally the excitation of the air noise radiated by the oil sump is reproduced, so as to complete the noise calculation and analysis. The calculation method considers the differences of the oil pump (excitation), the loss of the oil pressure pulsation generated by the oil circuit design (path), and the differences of the oil sump structure radiation noise (radiation source), thereby improving the noise evaluation precision.

[0021] In a third aspect, an engine is provided, which includes the oil circuit system in the above first aspect or any one of the possible embodiments of the first aspect. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a comparison schematic diagram of the oil sump noise spectrum of the engine of an embodiment of the present application; Figure 2 is a connection schematic diagram of the oil circuit system of an embodiment of the present application; Figure 3 is a connection schematic diagram of the oil circuit system in the related art; Figure 4 is an assembly schematic diagram of the oil circuit system in the related art; Figure 5 is an angle schematic diagram of an embodiment of the present application; Figure 6 is a structure schematic diagram of a buffer of an embodiment of the present application; Figure 7 is a flowchart of a design method of the oil circuit system of an embodiment of the present application; Figure 8 is a schematic diagram of a target angle of an embodiment of the present application; Figure 9 is a pressure fluctuation schematic diagram of an embodiment of the present application; Figure 10 is a comparison schematic diagram of outlet pressure of an embodiment of the present application.

[0023] Reference Signs: Oil pump 1, oil pump support 11, oil pump fixing bolt 12, Cooler 2, cooler fixing bolt 21, a first conduit 3, a second conduit 4, a buffer 5, a buffer cavity 51, a buffer inlet 52, a buffer outlet 53, an engine block 6, an oil pan 7. DETAILED DESCRIPTION

[0024] The technical solutions in the present application will be described in detail below with reference to the drawings. In the description of the embodiments of the present application, unless otherwise specified, " / " represents the meaning of or, for example, A / B can represent A or B: "and / or" in the text is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist together, and B exists alone, in addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0025] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features.

[0026] The vibration noise level of the oil pump of the engine is one of the important evaluation indexes of the comprehensive performance of the engine. The main function of the oil pan of the engine is to store oil and provide the engine with the oil reserve required for lubrication, to ensure that the oil pump has sufficient oil supply to each friction pair of the engine under any working condition, such as cold start, climbing, and sudden acceleration, and at the same time, it also has important auxiliary functions such as heat dissipation, impurity precipitation, and sealing. However, the oil pan is a thin-walled part, which is easily excited by the oil pump, crankshaft and other components inside the engine to radiate a large amount of noise, i.e. to produce engine radiation noise, especially after the balance shaft of the engine is cancelled, the overall background noise of the whole machine is reduced, making the oil pan noise problem more prominent, therefore, in the process of improving the NVH performance of the engine, it is extremely important to reduce the vibration noise component of the oil pan.

[0027] For example, Figure 1For the engine oil pan noise spectrum contrast chart, the noise spectrum curves measured in four directions (A-weighting) of the engine in three different states are shown respectively. Among them, Spectrum Four (A): indicates the A-weighted sound pressure level spectrum (i.e. the noise perceived by the human ear after weighting) measured in four directions (front, rear, left and right). A-weighting (A-weighting, denoted as dB(A)) is a kind of noise measurement method simulating the human ear hearing characteristics; rpm: indicates the engine speed, unit is revolutions per minute; dB(A): indicates the noise unit, A-weighted decibel, the smaller the value, the quieter the human ear feels. Among them, the red curve represents the noise spectrum curve of the original engine embodiment (i.e. the engine with a balance shaft) at a speed of 750.04 rpm, the curve number is 1, and the total boost level RMS (Root Mean Square, RMS) value in the frequency band of 400-3000 Hz is 66.22 dB(A); the green curve represents the noise spectrum curve of the engine embodiment without balance shaft at a speed of 746.63 rpm, the curve number is 2, and the total boost level RMS value in the frequency band of 400-3000 Hz is 63.35 dB(A); the blue curve represents the noise spectrum curve of the engine embodiment without balance shaft and with an external oil pump at a speed of 750.04 rpm, the curve number is 3, and the total boost level RMS value in the frequency band of 400-3000 Hz is 66.22 dB(A).

[0028] In combination Figure 1 The test data show that the oil pan radiation noise (400-3000 Hz frequency band) of the engine without an oil pump is reduced by about 2.6 dBA. The oil pan radiation noise of the engine is mainly composed of two parts: one part comes from the fluid excitation of the oil pump, and the other part comes from other background noise. With the optimization of the overall design of the engine, other background noise (such as combustion noise, mechanical noise) will continue to decrease, and in this case, the originally masked oil pump fluid excitation noise will be further highlighted. Therefore, in the engine with smaller background noise, the oil pan radiation noise caused by the fluid excitation of the oil pump is expected to become the main noise source. Therefore, a new optimization scheme needs to be developed to reduce this part of noise.

[0029] To solve the at least one technical problem, the oil circuit system is provided to increase the fluid pressure loss through the bend design between the oil pump and the cooler, reduce the pulse excitation caused by the oil pump, and achieve the purpose of reducing the engine radiation noise and improving the NVH performance of the engine. The oil circuit system of the present application will be described in detail below in conjunction with the drawings.

[0030] Figure 2 is a connection diagram of the oil circuit system of an embodiment of the present application.

[0031] Combination Figure 2 As shown, the oil circuit system of this application embodiment includes an oil pump 1, a cooler 2, a first pipeline 3, and a second pipeline 4.

[0032] The cooler 2 has an oil inlet and an oil outlet, with the oil outlet connected to the main oil circuit; the first pipe 3 and the second pipe 4 are connected, and the first pipe 3 is connected to the oil pump outlet of the oil pump 1, while the second pipe 4 is connected to the oil inlet of the cooler 2; the extension direction of the first pipe 3 and the extension direction of the second pipe 4 form an angle.

[0033] Specifically, this oil circuit system is used in engines, such as gasoline engines and diesel engines.

[0034] In related technologies, the engine's oil circuit system adopts... Figure 3 The oil circuit connection method shown is combined with Figure 4 As shown, the oil inlet of oil pump 1 is connected to the oil pan 7, and the oil pump outlet of oil pump 1 is connected to the oil inlet of cooler 2 through a straight oil pipe. The oil outlet of cooler 2 is connected to the main oil circuit. Furthermore, the housing of oil pump 1 is fixed to the engine block 6 above it by oil pump bracket 11 and oil pump fixing bolts 12. Cooler 2 is fixed to oil pan 7 by cooler fixing bolts 21. During engine operation, oil pump 1 draws oil from oil pan 7, pressurizes it, and outputs high-temperature, high-pressure oil. This oil then flows into cooler 2 through the straight oil pipe for cooling. The cooled oil enters the main oil circuit, which distributes the oil to various parts requiring lubrication and cooling, such as the crankshaft, camshaft, and turbocharger, before finally reaching oil pan 7 for storage.

[0035] Since the oil pump 1 typically uses a gear pump or rotary pump, its working principle is to transfer oil from the inlet to the outlet of the oil pump 1 through the meshing and disengagement of gear teeth or rotor cavities, thus completing the oil pumping. Because the meshing and disengagement of gear teeth or rotor cavities are performed discretely, taking a gear pump as an example, each pair of teeth completes one mesh, outputting a portion of oil. This results in the flow rate and pressure at the oil pump outlet not being a smooth straight line, but exhibiting periodic fluctuations as the gear rotation angle changes, generating flow pulsations. This, in turn, leads to pressure pulsations acting on the oil circuit system. The pressure pulsations act directly on the cooler, and are then transmitted to the oil pan 7 through the cooler fixing bolts 21, causing it to generate pulse vibrations.

[0036] exist Figure 3 In the illustrated embodiment, the outlet fluid of the oil pump 1 directly impacts the cooler 2, resulting in a large pressure surge and significant vibration and noise. Therefore, this application proposes an oil circuit design with a curved pipeline. For example... Figure 2 The oil circuit system includes a first pipeline 3 and a second pipeline 4, which are arranged at an angle to form a curved pipeline design.

[0037] The embodiment increases the pressure loss of the oil when flowing through the elbow pipeline, wherein, Figure 2 The fluid pressure loss of the elbow pipeline is greater than Figure 3 The fluid pressure loss of the elbow pipeline is greater than 1. Flow separation: inside the elbow, the fluid can separate from the pipe wall, forming a low-pressure vortex area; 2. Secondary flow: the elbow can cause the fluid to rotate perpendicular to the main flow direction (secondary flow), increasing additional friction and energy dissipation; 3. Streamline bending: the fluid is forced to change direction, part of its kinetic energy is consumed to overcome inertial forces and form complex flow patterns; 4. Turbulence enhancement: the elbow usually increases the turbulence intensity of the fluid, resulting in higher friction loss.

[0038] Therefore, in the embodiment shown, Figure 2 In the embodiment shown, the oil pumped by the oil pump 1 is output to the cooler 2 through the elbow pipeline design, by increasing the pressure loss of the oil during transportation, thereby reducing the pipe tap pressure value connected to the cooler, reducing the impact of the oil output by the oil pump 1 on the cooler 2, reducing vibration noise, and thereby achieving the purpose of reducing engine radiation noise and improving engine NVH performance.

[0039] In some embodiments of the present application, the included angle is 90°-160°.

[0040] That is, the included angle is in the range of (90°, 160°]. As Figure 5 As shown, the included angle between the first pipeline 3 and the second pipeline 4 can be selected as 100°, 110°, 150°, 160°, etc.

[0041] In this way, the included angle between the first pipeline 3 and the second pipeline 4 can be more reasonable, on the one hand, the pressure impact of the oil output by the oil pump 1 on the cooler 2 can be reduced through the design of the included angle, and the vibration noise of the oil pan caused is reduced, thereby reducing the engine radiation noise, on the other hand, it can prevent the fluid pressure loss from being too large due to the included angle being too small, which has adverse effects on the engine efficiency, and at the same time, it can prevent the fluid pressure loss from being too small due to the included angle being too large, which results in poor noise reduction effect.

[0042] In some embodiments of the present application, the oil circuit system further comprises: a buffer 5, the buffer 5 is arranged upstream of the oil inlet hole of the cooler 2 and is connected with the second pipeline 4.

[0043] Specifically, in combination with Figure 2As shown, the oil pump outlet of the oil pump 1 is connected to the cooler 2 through the first pipeline 3, the second pipeline 4 and the buffer 5 in sequence. In the working process, the oil is pumped out from the oil pump 1 and flows to the first pipeline 3, and then flows to the buffer 5 through the first pipeline 3 and the second pipeline 4 in sequence, and then flows into the cooler 2 after being buffered and attenuated by the buffer 5.

[0044] In this way, the fluid pressure pulse generated by the oil pump 1 is stepwise attenuated through the curved pipeline structure (the first pipeline 3 and the second pipeline 4) and the buffer 5, and the directional design of “the oil pump 1 → the curved pipeline → the buffer 5 → the cooler 2” forms an impedance-matched filtering structure, wherein the curved pipeline smoothes the medium-low frequency fluctuations in the fluid pressure pulse through the flow resistance and inertial effect, the buffer 5 absorbs the high frequency pressure pulse in the fluid pressure pulse, so that the fluid pressure entering the cooler 2 is more stable, and the pressure pulsation generated by the periodic oil discharge of the oil pump 1 is directly weakened, thereby reducing the fluid excitation force that excites the structure vibration from the source, so as to reduce the vibration noise generated by the oil sump, which not only satisfies lubrication but also has the effect of noise reduction.

[0045] In combination with Figure 2 and Figure 6 As shown, in some embodiments of the present application, the buffer 5 includes a buffer cavity 51, and a buffer inlet 52 and a buffer outlet 53 are respectively led out on the opposite two side walls of the buffer cavity 51, the buffer inlet 52 is connected to the second pipeline 4, the buffer outlet 53 is in communication with the oil inlet hole of the cooler 2, and the flow passage diameter of the buffer outlet 53 is smaller than that of the buffer inlet 52.

[0046] Specifically, the positions of the buffer inlet 52 and the buffer outlet 53 can be arranged according to actual conditions, for example, the buffer inlet 52 and the buffer outlet 53 can be arranged in alignment, or can be arranged staggered.

[0047] For example, the buffer outlet 53 and the buffer inlet 52 can be respectively arranged at the upper and lower end positions of the opposite two side walls of the buffer cavity 51, as shown in Figure 6 As shown, the buffer outlet 53 is arranged at the lower end position of one side wall of the buffer cavity 51, and the buffer inlet 52 is arranged at the upper end position of the other side wall of the buffer cavity 51. Then, in the working process of the oil system, the oil flows from the oil pump 1 to the second pipeline 4, and then flows to the buffer inlet 52 through the second pipeline 4 and the first pipeline 3 in sequence, and then flows into the buffer cavity 51 through the buffer inlet 14, and finally flows to the cooler 2 through the lower end buffer outlet 53. In this way, by staggering the buffer inlet 52 and the buffer outlet 53, the buffer path can be lengthened, and sufficient buffering can be achieved, so that the medium can be fully buffered before being discharged through the buffer outlet 53.

[0048] The flow passage diameter of the buffer outlet 53 and the flow passage diameter of the buffer inlet 52 can be set according to actual conditions, for example, a preset diameter difference between the flow passage diameter of the buffer outlet 53 and the flow passage diameter of the buffer inlet 52 can be preset, and then the flow passage diameter of the buffer outlet 53 is calculated based on the preset diameter difference after the flow passage diameter of the buffer inlet 52 is determined according to the application scenario of the oil circuit system; in addition, the diameter deviation allowable range between the flow passage diameter of the buffer outlet 53 and the flow passage diameter of the buffer inlet 52 can also be preset, and one of the diameter deviation values is selected as the preset diameter difference according to the design requirements of the oil circuit system for the structural design of the buffer 5.

[0049] For example, the preset diameter difference between the flow passage diameter of the buffer outlet 53 and the flow passage diameter of the buffer inlet 52 is 1 mm, as shown in Figure 5 The flow passage diameter of the buffer inlet 52 is 18 mm and the flow passage diameter of the buffer outlet 53 is 17 mm.

[0050] In this way, the diameter of the buffer outlet 53 of the buffer 5 is smaller than that of the buffer inlet 52, a gradually changing cross-section hydraulic impedance can be constructed, and selective attenuation of high-frequency pulses of fluid pressure pulses is realized, so as to attenuate high-frequency pulses and improve the effect of vibration reduction and noise reduction.

[0051] The oil circuit system design method is also provided in the embodiments of the present application.

[0052] In the oil circuit system in the above embodiments, the design target of the elbow pipeline is to reduce the pipe tap pressure value connected to the cooler, but the local loss coefficient of the elbow pipeline is usually much larger than the friction coefficient of the straight pipeline of the same length, for example, the local loss of a standard 90° elbow can be equivalent to the friction loss of a straight pipe of several tens of times the pipe diameter, and therefore, if the angle of the elbow pipeline is too large, it is easy to cause additional average pressure loss and reduce the engine performance. In order to optimize the design of the elbow pipeline, the oil circuit system design method is provided to further optimize and select the structure of the above oil circuit system.

[0053] As shown in Figure 7 The oil circuit system design method of the embodiments of the present application can include the following steps: S1, constructing an oil circuit connection model of the oil circuit system.

[0054] Specifically, according to the design parameters of the oil circuit system determined in advance, such as the initial pipe diameter, length, included angle, oil pump installation position, etc., an initial connection three-dimensional model of the oil circuit system between the oil pump and the oil pan is constructed as the oil circuit connection model of the oil circuit system.

[0055] S2, obtaining an initial oil pressure amplitude of the oil circuit connection model, and calculating an amplitude difference between the initial oil pressure amplitude and a preset pressure amplitude.

[0056] Specifically, the detection position of the oil pressure amplitude value can be set according to requirements, for example, the oil inlet hole of the cooler is selected as the pressure monitoring point. At this time, according to the operating boundary conditions of the engine system, such as the oil pump output flow rate under steady state, the fluid dynamics calculation is performed on the oil circuit connection model to obtain the oil pressure amplitude value at the oil inlet hole of the cooler.

[0057] For example, first, the internal flow region is extracted as the calculation domain according to the above oil circuit connection model, a three-dimensional fluid domain geometric model is established, then the three-dimensional fluid domain geometric model is meshed using a structured network or an unstructured network, a mesh file is calculated, and further combined with the mesh file, the preset boundary conditions and the preset parameters, the oil inlet hole of the cooler is subjected to three-dimensional mechanics calculation to obtain the time series data at the oil inlet hole of the cooler, and a time domain graph of the oil pressure fluctuation is constructed, and then the maximum amplitude in the time domain graph of the oil pressure fluctuation is taken as the initial pressure amplitude.

[0058] The preset pressure amplitude can be set according to actual conditions, which is the expected pressure amplitude. The amplitude difference between the preset pressure amplitude and the initial pressure amplitude is obtained to evaluate the noise condition of the current oil circuit connection model, which is used for subsequent structural improvement of the model.

[0059] S3, adjust the included angle based on the amplitude difference until the oil pan noise of the oil circuit connection model satisfies the preset noise attenuation condition, and generate at least one design parameter of the oil circuit system.

[0060] Specifically, a mapping table between the amplitude difference and the included angle adjustment value can be constructed in advance. After the amplitude difference between the initial oil pressure amplitude and the preset pressure amplitude is calculated, the included angle adjustment value is obtained by looking up the table, and the initial included angle is corrected according to the included angle adjustment value. For example, when the amplitude difference is positive and the initial oil pressure amplitude is greater than the preset pressure amplitude, it is considered that the pressure at the oil inlet hole of the cooler is too large, the fluid output by the oil pump will have a large impact on the cooler, resulting in a large oil pan noise. At this time, the included angle needs to be adjusted to a smaller angle according to the amplitude difference, so as to increase the fluid pressure loss caused by the curved pipe formed by the first pipe and the second pipe; when the amplitude difference is negative and the initial oil pressure amplitude is less than the preset pressure amplitude, it is considered that the pressure at the oil inlet hole of the cooler satisfies the noise reduction requirement, at this time, the current included angle can be kept unchanged as the included angle design parameter of the oil circuit system, or the included angle can be adjusted to a larger angle according to the amplitude difference, so as to prevent the included angle of the curved pipe from being too small and causing excessive pressure loss, which reduces the engine performance.

[0061] After the included angle is adjusted according to the amplitude difference value, whether the oil pan noise of the oil circuit connection model meets the preset noise attenuation condition is evaluated. When the oil pan noise of the oil circuit connection model meets the preset noise attenuation condition, the design parameters of the current model are fixed for production of the oil circuit system, and the design parameters of the oil circuit system can include the included angle, the pipe size, the buffer size, and the like. If the oil pan noise still does not meet the preset noise attenuation condition, the included angle can be continuously adjusted, or other parameters can be adjusted until the oil pan noise of the oil circuit connection model meets the preset noise attenuation condition, and the design parameters of the current model are fixed as the design parameters of the oil circuit system for production of the oil circuit.

[0062] The preset noise attenuation condition is a pre-set flow-induced noise evaluation condition. When the oil pan noise of the oil circuit connection model meets the preset noise attenuation condition, it is considered that the oil pan radiation noise caused by the fluid excitation of the oil pump is small to meet the noise reduction requirement. When the oil pan noise of the oil circuit connection model does not meet the preset noise attenuation condition, it is considered that the fluid excitation of the oil pump will still bring large oil pan radiation noise, which does not meet the noise reduction requirement. Exemplarily, the preset noise attenuation condition can be that the oil pan noise is reduced to a target noise value. When the oil pan noise of the oil circuit connection model is ≤ the target noise value, it is considered that the preset noise attenuation condition is met. The preset noise attenuation condition can also be that the oil pan noise is reduced by a preset noise value. When the noise difference value between the initial oil pan radiation noise of the oil circuit connection model and the oil pan radiation noise obtained after the included angle is adjusted is ≥ the preset noise value, it is considered that the preset noise attenuation condition is met.

[0063] This embodiment realizes collaborative improvement of lubrication performance and NVH target based on the design of the curved pipe. On the one hand, by reducing the pipe tap pressure value connected to the cooler, the source of fluid excitation force transmitted to the oil pan is directly weakened, the middle and low frequency structural radiation noise of the thin-walled part is effectively inhibited, and the oil pan radiation noise is reduced. On the other hand, the included angle of the actual curved pipe is adjusted based on the amplitude difference value. Under the premise of controlling the flow resistance and pressure loss, the pressure pulsation of a specific frequency band is further attenuated by changing the pipe stiffness and flow guide form. Such adaptive structure parameter matching not only guarantees the stability of the oil flow and engine performance, but also reduces the risk of engine high-frequency howling and fluid resonance by precisely adjusting the included angle, thereby improving the vibration and noise quality of the gasoline engine in three dimensions of source governance, path optimization, and system reliability, and achieving the purpose of improving the engine NVH performance.

[0064] In an embodiment of the present application, in the case that the oil circuit system further comprises a buffer, the included angle is adjusted based on the amplitude difference value until the oil pan noise of the oil circuit connection model satisfies the preset noise attenuation condition, comprising: determining an angle adjustment range according to the amplitude difference value; matching the angle adjustment range based on the target design parameters of the oil circuit system to obtain a target angle, and adjusting the included angle according to the target angle; in the case that the oil pan noise of the oil circuit connection model does not satisfy the preset noise attenuation condition, adjusting the cavity volume of the buffer according to the oil pressure amplitude of the oil circuit connection model and the initial oil pressure amplitude until the oil pan noise satisfies the preset noise attenuation condition.

[0065] Specifically, in combination with Figure 2 As shown in the figure, the oil circuit system further comprises a buffer 5, and the oil pump outlet of the oil pump 1 is connected to the cooler 2 through the first pipeline 3, the second pipeline 4 and the buffer 5 in sequence. In this oil circuit connection scheme, the oil circuit system composed of the curved pipeline structure and the buffer gradually reduces the pressure fluctuation from the oil pump-pipeline-cooler, thereby reducing the vibration noise generated by the oil pan, achieving both lubrication and noise reduction effects.

[0066] In the design process of the oil circuit system, first, the angle adjustment range is determined according to the amplitude difference value, for example, the maximum angle adjustment value can be obtained by looking up the amplitude difference value table, and the angle adjustment range is constructed according to the maximum angle adjustment value and the preset minimum angle adjustment value.

[0067] Then, a target angle is selected from the obtained angle adjustment range as a target angle in combination with the target design parameters of the oil circuit system to adjust the included angle between the first pipeline and the second pipeline. The target angle can be the included angle of the first pipeline and the second pipeline, so that after the target angle is determined, the included angle of the first pipeline and the second pipeline is directly adjusted to the target angle; the target angle can also be the included angle correction angle of the first pipeline and the second pipeline, so that after the target angle is determined, the included angle of the first pipeline and the second pipeline is adjusted from the current included angle to the target angle, such as reducing the target angle.

[0068] The target design parameters of the oil circuit system can be selected according to the influence degree of each design parameter in the system on the performance of the lubrication system and the engine NVH. For example, the target design parameters include the oil pump arrangement and the liquid level, wherein the oil pump arrangement refers to the spatial position, mounting method and relative relationship with the oil pan of the oil pump, and the liquid level refers to the liquid level of the oil in the oil pan, which can include the static liquid level (when the engine is off) and the dynamic liquid level (during operation, affected by shaking and tilting). In the target angle determination process, the target angle is obtained by matching the oil pump arrangement and the liquid level with the angle adjustment range, for example, a mapping relationship between the oil pump arrangement-liquid level-angle adjustment range-target angle can be constructed in advance, and in the application process, the corresponding target angle is obtained by looking up the table. For example, the target angle is determined by matching the oil pump arrangement and the liquid level with the angle adjustment range, and the target angle is obtained by looking up the table. Figure 8For example, the included angle between the first pipeline and the second pipeline = a + 90°, the included angle adjustment process is the adjustment process of a, assuming that the angle adjustment range of a (0°, 70°) is determined based on the amplitude difference, then in the design example, a is determined to be 45° in combination with the target design parameters of the engine, and then the included angle of the first pipeline and the second pipeline is adjusted to 145° based on a, and the oil pan noise of the oil circuit connection model after the included angle adjustment is measured.

[0069] If the oil pan noise of the oil circuit connection model after the included angle adjustment meets the preset noise attenuation condition, the design is required to be frozen. If the oil pan noise of the oil circuit connection model after the included angle adjustment does not meet the preset noise attenuation condition, the cavity volume of the buffer is further adjusted according to the oil pressure amplitude of the oil circuit connection model after the included angle adjustment, until the oil pan noise of the oil circuit connection model meets the preset noise attenuation condition. For example, a mapping table between the amplitude difference between the oil pressure amplitude of the oil circuit connection model and the initial oil pressure amplitude and the cavity volume can be pre-set, and in the case where it is determined that the oil pan noise of the oil circuit connection model after the included angle adjustment does not meet the preset noise attenuation condition, the cavity volume is obtained by table lookup according to the oil pan noise of the oil circuit connection model after the included angle adjustment and the initial oil pressure amplitude, for parameter adjustment of the buffer.

[0070] It can be understood that after adjusting the cavity volume of the buffer, the oil pan noise of the oil circuit connection model needs to be re-acquired to determine whether the oil pan noise meets the preset noise attenuation condition, and if it meets, the design is frozen to determine the oil circuit design parameters; if it still does not meet, the oil circuit connection model can be continuously adjusted in sequence according to the order of included angle adjustment and cavity volume adjustment, until the preset noise attenuation condition is met.

[0071] In this embodiment, the optimal angle value is determined from the angle adjustment range determined based on the amplitude difference in combination with other design parameters of the oil circuit system, the included angle between the first pipeline and the second pipeline is adjusted to reduce the fluid pressure fluctuation amplitude, and through the included angle adjustment, the first four peak pressure fluctuations in Figure 9 can be effectively reduced, and then the noise generated by the fluid pulsation excitation is reduced, so as to achieve the purpose of optimizing the engine NVH performance. Then in the case where the oil circuit connection model after the included angle adjustment meets the preset noise attenuation condition, the design is frozen to determine the design parameters of the oil circuit; if it does not meet the preset noise attenuation condition, the cavity volume of the buffer is adjusted, and through the cavity volume adjustment, the first four peak pressure fluctuations in Figure 9The last four peak pressure fluctuations in the above-mentioned purpose of attenuating high-frequency pulses, thereby, through the cyclic adjustment sequence of the included angle adjustment cavity volume adjustment, beyond the single parameter optimization, the global shaping of the hydraulic pulsation spectrum is realized, and through iterative adjustment, the system can adaptively balance the propagation impedance of pressure waves of different frequencies, such as the included angle change mainly regulates the low-frequency pressure reflection phase, and the inner diameter adjustment fine-tunes the flow resistance and inertial effect of high-frequency pulsation. This coupled design broadens the attenuation frequency band of pressure fluctuations, reduces the resonance risk of the oil sump in a wide speed range, suppresses noise generation at the source, and builds a frequency-selective pulse modulation under the premise of ensuring controllable system pressure loss, significantly improving the NVH smoothness of the engine under all operating conditions, and achieving balanced optimization of pressure fluctuations.

[0072] In some embodiments of the present application, the angle adjustment range is determined according to the amplitude difference value, including: obtaining an initial angle of the included angle, and determining a maximum allowed adjustment angle according to the initial angle; determining a correction angle according to the amplitude difference value, the preset oil viscosity and the preset oil flow rate; and correcting the maximum allowed adjustment angle according to the correction angle to determine the angle adjustment range.

[0073] Specifically, the oil path design method starts with the angle of the included angle of the oil path connection model being an initial angle, which can be set according to actual conditions. For example, the initial angle is set to 175°, and a mapping relationship between the initial angle and the maximum allowed adjustment angle is set. During the design process of the oil path system, the corresponding maximum allowed adjustment angle is obtained according to the initial angle. In addition, the mapping relationship between the initial angle and the maximum allowed adjustment angle can be further constructed in combination with other design parameters of the oil path system.

[0074] The oil viscosity represents the ease of oil flow and internal friction characteristics, and the oil flow rate represents the softening demand of the engine system. The preset oil viscosity and the preset oil flow rate are the design basis and premise of the oil path system. Before executing the oil path system design method of the present embodiment, first construct the oil path system and the oil path connection model based on the preset oil viscosity and the preset oil flow rate, and then execute the above-mentioned included angle adjustment, cavity volume adjustment and other processes. In the included angle adjustment process, the correction angle that can meet the pressure amplitude adjustment demand is calculated in combination with the amplitude difference value of the pressure pulse, the preset oil viscosity and the preset oil flow rate, and the maximum allowed adjustment angle is corrected according to the correction angle, so that the angle values in the angle adjustment range can all meet the pressure adjustment demand. Then, a target angle value is selected from the obtained angle adjustment range as a target angle to adjust the included angle between the first pipeline and the second pipeline in combination with the target design parameters of the oil path system.

[0075] The embodiment first determines the maximum allowable adjustment angle allowed by the oil circuit design according to the initial angle, draws a safety boundary to ensure the reliability of the oil circuit connection and the feasibility of the assembly, and then adjusts the maximum allowable adjustment angle in combination with the amplitude difference between the initial engine oil pressure amplitude and the preset pressure amplitude to obtain an angle adjustment range that meets the oil circuit design requirements and satisfies the pressure amplitude adjustment, so as to intelligently match an actual adjustment interval with noise reduction effect and system compatibility within the safety boundary. Not only the risk of flow resistance increase or structural interference caused by blindly pursuing noise reduction is avoided, but also the bend angle can accurately correspond to the pulsation characteristics of a specific engine working condition through the quantitative feedback of the pressure signal, thereby improving the scientificity of the angle design.

[0076] In some embodiments of the present application, the correction angle is determined according to the amplitude difference, the preset lubricating oil viscosity and the preset lubricating oil flow rate, including: obtaining a product of the preset engine oil viscosity and the square of the preset engine oil flow rate to obtain a first value; obtaining a ratio of twice the amplitude difference to the first value to obtain a second value; obtaining a difference between the second value and a preset constant to obtain a third value; obtaining a product of the first preset coefficient and the third value to obtain a fourth value, and determining the correction angle based on the fourth value.

[0077] That is, the correction angle is calculated based on the following formula: , (1) wherein, is the correction angle, is the preset engine oil viscosity, is the preset engine oil flow rate, is the amplitude difference, is the preset constant, is the first preset coefficient.

[0078] The initial engine oil pressure amplitude of the oil circuit connection model is obtained, the amplitude difference between the initial engine oil pressure amplitude and the preset pressure amplitude is calculated, the amplitude difference is substituted into formula (1) to calculate the correction angle, and then the maximum allowable adjustment angle of the first pipe component and the second pipe component is adjusted by the correction angle to obtain an angle adjustment range that satisfies the pressure amplitude adjustment, so as to select an optimal angle as a target angle from the angle adjustment range in combination with the target design parameters of the engine, and the target angle is used to adjust the included angle between the first pipe and the second pipe.

[0079] The embodiment substitutes the amplitude difference into the above correction angle calculation formula after calculating the amplitude difference, thereby improving the construction precision and efficiency of the correction angle.

[0080] In some embodiments of this application, determining the angle adjustment range by correcting the maximum permissible adjustment angle based on the correction angle includes: obtaining the angle difference between the maximum permissible adjustment angle and the correction angle to obtain the maximum target adjustment angle, and determining the angle adjustment range based on the maximum target adjustment angle. Adjusting the included angle based on the target angle includes: reducing the included angle to a smaller target angle.

[0081] Specifically, in combination Figure 8 As shown, assuming the maximum allowable adjustment angle is 90°, the formula for calculating the maximum target adjustment angle is as follows: α = 90 - β, (2) Where α is the maximum target adjustment angle, 90 is the maximum allowable adjustment angle, and β is the correction angle.

[0082] Substituting formula (1) into formula (2), we obtain the formula for calculating the maximum target adjustment angle: (3) Where α is the maximum target adjustment angle, and 90 is the maximum allowable adjustment angle. To preset the oil viscosity, To preset the oil flow rate, The difference in amplitude. As a preset constant, This is the first preset coefficient.

[0083] Assuming the calculated maximum target adjustment angle is 70°, the angle adjustment range is (0°, 70°). Then, by matching the target design parameters of the oil circuit system with the angle adjustment range, an optimal angle within the adjustment range is selected as the target angle. The angle between the first and second pipelines is reduced to the target angle. As the oil passage angle of the curved pipeline decreases, the pressure loss of the oil flowing through the oil circuit increases, and the amplitude difference Δp of the pressure pulse decreases. This reduces the impact of the fluid output by the oil pump on the cooler, thus reducing the resulting oil pan noise. In this embodiment, after obtaining the initial oil pressure amplitude of the oil circuit connection model and calculating the amplitude difference between the initial oil pressure amplitude and the preset pressure amplitude, the amplitude difference is substituted into formula (3) to calculate the maximum target adjustment angle, so as to obtain the angle adjustment range that satisfies the pressure amplitude adjustment. Then, combined with the target design parameters of the oil circuit system, the optimal angle is selected from the angle adjustment range as the target angle to reduce the angle between the first pipeline and the second pipeline. As the oil passage angle decreases, the pressure loss increases, the amplitude of pressure pulsation is reduced, the amplitude difference is reduced, the impact of the fluid output by the oil pump on the cooler is reduced, and the oil pan noise value caused by the excitation of the fluid output by the oil pump is reduced, thereby optimizing the oil circuit design efficiency. In some embodiments of this application, adjusting the cavity volume of the buffer component based on the oil pressure amplitude of the oil circuit connection model after the included angle adjustment includes: obtaining the actual amplitude difference between the oil pressure amplitude of the oil circuit connection model after the included angle adjustment and the preset pressure amplitude; determining the target cavity cross-sectional area based on the actual amplitude difference and the current cavity cross-sectional area of ​​the buffer component, so as to adjust the cavity volume of the buffer component according to the target cavity cross-sectional area.

[0084] Specifically, based on the difference between the initial oil pressure amplitude and the preset pressure amplitude of the oil circuit connection model, the angle between the first and second pipes of the oil circuit connection model is adjusted. If the oil circuit connection model still does not meet the noise attenuation requirements, fluid dynamics calculations are performed on the oil circuit connection model to obtain the oil pressure amplitude of the oil circuit connection model after the angle adjustment. For details, please refer to the description of the method for obtaining the oil pressure amplitude above.

[0085] Then, the difference between the oil pressure amplitude of the oil circuit connection model after the included angle adjustment and the initial pressure amplitude is calculated to obtain the actual amplitude difference. Based on this actual amplitude difference, the current cavity cross-sectional area of ​​the buffer is adjusted to determine the target cavity cross-sectional area. For example, a mapping relationship between the actual amplitude difference and the cross-sectional area adjustment value can be pre-established. After calculating the actual amplitude difference, the cross-sectional area adjustment value is determined, and the sum of the current cavity cross-sectional area of ​​the buffer and the cross-sectional area adjustment value is calculated as the target cavity cross-sectional area. After calculating the target cavity cross-sectional area, the actual cross-sectional area of ​​the buffer cavity is adjusted to the target cavity cross-sectional area to adjust the cavity volume of the buffer. By increasing the cavity size of the buffer, the attenuation capability of the pressure pulse is increased.

[0086] This embodiment determines the target cavity cross-sectional area of ​​the buffer component based on the actual amplitude difference between the oil pressure amplitude of the oil circuit connection model and the preset pressure amplitude. This allows the inner diameter of the buffer cavity to be adaptively designed according to the current oil circuit characteristics, thereby obtaining the cavity volume of the buffer component that meets the pressure pulse attenuation requirements. This improves the parameter adjustment accuracy and adaptation effect of the buffer component.

[0087] In some embodiments of this application, determining the target cavity cross-sectional area based on the actual amplitude difference and the current cavity cross-sectional area of ​​the buffer includes: obtaining the ratio between the actual amplitude difference and the oil pressure amplitude of the oil circuit connection model after the included angle adjustment to obtain the target attenuation value; obtaining the ratio between the target attenuation value and ten to obtain the target exponent, and obtaining the difference between the target exponent raised to the power of ten and one to obtain the fifth value; obtaining the product of the arithmetic square root of the sixth value and two to obtain the sixth value; calculating the angular wave number according to the preset oil pressure pulsation frequency, and obtaining the product of the angular wave number and the cavity length of the buffer to obtain the radian phase change value; obtaining the sine value of the radian phase change value to obtain the seventh value; obtaining the ratio between the sixth value and the seventh value to obtain the first coefficient; obtaining the sum of the second preset coefficient and the first coefficient to obtain the second coefficient; and obtaining the product of the current cavity cross-sectional area and the second coefficient to obtain the target cavity cross-sectional area.

[0088] Specifically, the formula for calculating vibration pulsation attenuation is as follows: (4) (5) (6) Where T is the attenuation value. This is the actual amplitude difference. The oil pressure amplitude of the oil circuit connection model after the included angle adjustment. The length of the buffer cavity. This represents the current cross-sectional area of ​​the cavity. The target cavity cross-sectional area, To preset the oil pressure pulsation frequency, The speed is 1200 m / s, and k is the angular wave number.

[0089] Combining the above formulas (4)-(6), the formula for calculating the cross-sectional area of ​​the target cavity is as follows: (7) in, , where is the target attenuation value.

[0090] In this embodiment, the angle between the first and second pipes of the oil circuit connection model is adjusted based on the difference between the initial oil pressure amplitude and the preset pressure amplitude of the oil circuit connection model. If the oil circuit connection model after the angle adjustment does not meet the noise attenuation requirements, the actual difference between the oil pressure amplitude and the preset pressure amplitude of the oil circuit connection model is obtained. The actual difference is substituted into formula (7) to calculate the cross-sectional area of ​​the target cavity, which is used to adjust the cavity volume of the buffer component, thereby improving the parameter adjustment accuracy and adjustment efficiency of the buffer component.

[0091] In some embodiments of this application, after adjusting the angle between the first pipeline and the second pipeline according to the target angle, the method further includes: obtaining the initial oil pan noise of the oil circuit connection model and the oil pan noise of the oil circuit connection model after the angle adjustment; if the noise difference between the initial oil pan noise and the oil pan noise of the oil circuit connection model after the angle adjustment is less than or equal to a preset noise attenuation value, determining that the oil pan noise of the oil circuit connection model after the angle adjustment does not meet the preset noise attenuation condition; if the noise difference between the initial oil pan noise and the oil pan noise of the oil circuit connection model after the angle adjustment is greater than the preset noise attenuation value, determining that the oil pan noise meets the preset noise attenuation condition.

[0092] Specifically, after adjusting the angle between the first and second pipelines based on the amplitude difference, the pulsating pressure of the fluid output from the computer oil pump on the model surface of the oil circuit connection model after the angle adjustment is used to convert the oil pan noise caused by the fluid output from the oil pump. At the same time, the initial oil pan noise of the oil circuit connection model is acquired, and the oil pan noise of the oil circuit connection model after the angle adjustment is compared with the initial oil pan noise to determine whether the preset noise attenuation condition is met.

[0093] Calculate the noise difference ΔT between the initial oil pan noise and the oil pan noise of the oil circuit connection model after the included angle adjustment. When ΔT ≤ the preset noise attenuation value, it is considered that the oil pan noise does not meet the preset noise attenuation condition and the cavity volume of the buffer needs to be further adjusted to supplement the pulse attenuation capability of the oil circuit system. When ΔT > the preset noise attenuation value, it is considered that the oil pan noise meets the preset noise attenuation condition.

[0094] This embodiment identifies whether the preset noise attenuation condition is met based on the difference between the initial oil pan noise and the oil pan noise of the adjusted model, thus ensuring the accuracy of noise attenuation identification and judgment.

[0095] In some embodiments of this application, the oil circuit method of the engine further includes: extracting the fluid flow region of the oil circuit connection model to construct a corresponding flow channel model; performing fluid dynamics calculations on the flow channel model based on preset boundary conditions to obtain the pressure fluctuation excitation force; identifying the corresponding oil pressure amplitude based on the pressure fluctuation excitation force and the target monitoring position; and mapping the pressure fluctuation excitation force to the acoustic mesh corresponding to the flow channel model to obtain the corresponding oil pan noise.

[0096] Specifically, the fluid flow region of the oil circuit connection model is first extracted. This fluid flow region can include the internal flow channels of the oil pump, the internal flow channels of the oil circuit, the internal flow channels of the buffer components, and the internal flow channels of the oil cooler. A continuous fluid region mesh suitable for computational fluid dynamics is then generated as the flow channel model. Unstructured mesh generation can be performed using mesh generation tools.

[0097] Preset boundary conditions refer to the limitations imposed on the computational boundaries during fluid dynamics calculations. These conditions can be set based on the engine's oil circuit operating conditions, such as fluid type (engine oil), density, viscosity, oil circuit inlet pressure, flow rate, temperature, oil circuit geometry, pipe diameter, and bending angle. These boundary conditions are used to restrict the simulation process. Pressure fluctuation excitation force refers to the time-varying pressure load acting on a solid wall surface due to unsteady fluid flow. It is the fundamental physical excitation source for structural vibration and radiated noise (flow-induced noise), and can be specifically represented by pressure fluctuation data.

[0098] After obtaining the flow channel model, within the preset boundary conditions, the three-dimensional pressure field and velocity field generated by the fluid output by the computer oil pump flowing in the flow channel model are calculated, and the pressure fluctuation data changing with time are extracted to obtain the pressure fluctuation excitation force.

[0099] In addition, detection points or monitoring surfaces are set at the target monitoring location of the fluid model (such as the oil inlet of the cooler), and pressure fluctuation data of the pressure signal at that location are extracted to obtain the original pressure fluctuation excitation force acting on the structure at the target monitoring location. The pressure fluctuation excitation force at the target monitoring location is time-domain pressure data. To further analyze the excitation characteristics, a fast Fourier transform is performed on the time-domain pressure data to convert it to the frequency domain, obtaining the pressure amplitude distribution spectrum for each frequency component, i.e., the oil pressure pulsation spectrum. This pressure amplitude distribution spectrum shows the relationship between pressure fluctuation amplitude and frequency. As a quantified oil pressure amplitude distribution, it can be directly used to evaluate the intensity and frequency characteristics of fluid excitation, identify the pressure amplitude distribution at the target monitoring location, and obtain the oil pressure amplitude.

[0100] After obtaining the pressure fluctuation excitation force, a coupling tool is used to map the obtained pressure fluctuation excitation force to the acoustic mesh corresponding to the flow channel model, serving as the input excitation source. The known fluid excitation load is indirectly predicted through the system transfer function via the acoustic mesh to obtain the corresponding oil pan noise. The acoustic mesh is a numerical model specifically designed for acoustic simulation calculations. It divides the sound propagation medium (such as air or water) into a large number of discrete small units to solve for physical phenomena such as sound wave propagation, reflection, scattering, and diffraction using numerical methods (such as the finite element method or boundary element method). In this embodiment, the acoustic mesh has the same structure as the channel model and can be generated by mapping from the fluid model. Specifically, the fluid model is used as a basis, simplified / reconstructed to generate an acoustic mesh that meets the acoustic wavelength requirements. The mesh is then imported into the acoustic software and its acoustic properties (density, sound velocity, etc.) are set for subsequent noise analysis.

[0101] For example, the acquired pressure fluctuation excitation force is mapped to the corresponding nodes of the acoustic mesh according to the location information. Using a numerical solver based on the acoustic boundary element method or finite element method, the sound pressure response from a unit vibration at each node (representing a point on the structural surface) to the target monitoring location is calculated, yielding the acoustic transfer function matrix. Simultaneously, this is combined with the structural finite element model or directly using the structural vibration transfer function obtained beforehand through hammer impact testing or exciter testing. Then, the acquired pressure fluctuation excitation force and the transfer function of the corresponding path are subjected to matrix operations and energy superposition to calculate the frequency domain sound pressure spectrum at the target monitoring location. This spectrum is then integrated to obtain the total sound pressure level or sound power level. Therefore, based on the pressure excitation source, noise propagation calculations are performed on the flow channel model to predict the sound pressure level or sound power level, which is used to analyze whether the model meets the preset noise attenuation conditions.

[0102] This embodiment constructs a virtual prototype encompassing the entire chain from fluid excitation and structural transmission to sound radiation. It reproduces the entire physical process from the generation of excitation by the oil pump, to its transmission and modulation through the oil passages, and finally to the radiation of airborne noise from the oil pan, thus completing noise calculation and analysis. This calculation method considers the differences in oil pump performance (excitation), the loss due to oil pressure pulsation caused by the oil passage design (path), and the differences in noise radiation from the oil pan structure (radiation source). NVH evaluation is performed based on the oil pump flow passage arrangement, improving the accuracy of noise assessment. This not only significantly shortens the NVH calibration cycle and reduces testing costs, but also, by revealing the intrinsic relationship between "pump source-path-response," provides a reliable digital foundation and design optimization basis for a systematic noise reduction scheme, from source excitation optimization and transmission path modulation to radiation structure design.

[0103] As a specific embodiment of this application, the connection of the oil circuit system is as follows: Figure 2 As shown, the engine oil flows from the oil pump 1 to the first pipeline 3, and then through the first pipeline 3, the second pipeline 4, and the buffer 5 in sequence, before flowing to the cooler 2. This scheme, through the oil circuit system composed of the designed pipeline structure and the buffer, gradually reduces the pressure fluctuation of the engine oil from the oil pump to the oil circuit to the cooler, thereby reducing the vibration noise generated by the fluid output from the oil pump in the oil pan. Thus, while meeting the lubrication requirements, it achieves a noise reduction effect.

[0104] As a specific embodiment of this application, the design method of the oil circuit system may include the following steps: The first step is to establish an oil circuit connection model for the oil pump and oil pan, and determine the oil output quantity Q of the oil pump and the flow channel diameter D under steady state, thereby calculating the flow velocity V= To determine the boundary conditions.

[0105] Step 2: Measure the oil pressure fluctuation diagram of the oil circuit connection model, determine the initial oil pressure amplitude, and select the pressure to be adjusted, i.e., the amplitude difference Δp, in combination with the preset expected oil pressure amplitude, so as to determine the design oil circuit angle based on Δp in the future.

[0106] Step 3: Substitute the pressure amplitude Δp into the calculation formula (3) to calculate the maximum target adjustment angle, so as to obtain the angle adjustment range.

[0107] It is understandable that as the oil passage angle decreases, the pressure loss when the oil flows through increases, thereby reducing the pressure pulsation amplitude. Step 4: Based on factors such as the oil pump layout and oil level, determine the optimal value from the angle adjustment range to adjust the angle between the first and second pipelines.

[0108] Step 5: Measure the noise at the oil inlet or outlet of the cooler after the angle adjustment, and use it as the oil pan noise to evaluate whether the noise attenuation value meets the preset noise attenuation conditions.

[0109] Assuming a noise reduction of 6dB is used as the evaluation standard to assess whether the pipeline angle design and the cavity design of the buffer component meet the preset noise reduction conditions, the simulated noise reduction value (the noise difference between the initial oil pan noise and the oil pan noise) is compared with the target value (6dB). If the requirements are met, the design is frozen. For example, when the angle α is 45°, if the noise reduction of 400~3000HZ is greater than 6dB, then α is output as 45° as the design parameter of the oil circuit. If not, step 6 is executed.

[0110] Step 6: Calculate the amplitude deviation between the measured oil pressure amplitude and the preset pressure amplitude of the model after the included angle adjustment, and substitute it into formula (7) to obtain the target cavity cross-sectional area of ​​the buffer component. Thus, by designing the cavity volume of the buffer component, the pulsation amplitude is reduced, the pressure pulsation is attenuated, until the preset noise attenuation condition is met.

[0111] This application aims to reduce pressure pulsation in the oil pipeline; the oil system piping scheme is as follows: Figure 3 The 180° angle shown is changed to Figure 8 The included angle θ is shown as 90° + α, where 90° + α > 90° and 90° + α ≤ 160°, with α ranging from 0° to 70°. For example, ... Figure 10 As shown, V0 is the outlet pressure fluctuation curve corresponding to a straight pipe with a 180° angle, and V1 is the outlet pressure fluctuation curve corresponding to a pipe with a 135° angle. The design angle of the pipe is changed from 180° to 135°, which reduces the pressure pulsation of the oil pipe. The outlet can correspond to the oil inlet of the cooler.

[0112] The oil circuit and buffer design method proposed in this embodiment reduces the amplitude of low-frequency and high-frequency pressure pulsations, reduces the impact of the fluid output from the oil pump on the cooler, thereby reducing the oil pan radiated noise caused by the fluid output from the oil pump, improving the sound quality, and solving the NVH problem of high oil pan noise caused by the direct impact of the oil pump outlet on the cooler in related technologies.

[0113] In summary, the oil circuit design method of this application embodiment first constructs an oil circuit connection model of the oil circuit system and obtains the initial oil pressure amplitude of the oil circuit connection model. It then calculates the amplitude difference between the initial oil pressure amplitude and a preset pressure amplitude. Next, based on the amplitude difference, it adjusts the angle between the first and second pipelines until the oil pan noise of the oil circuit connection model meets a preset noise attenuation condition, generating at least one design parameter for the oil circuit. Thus, this method increases fluid pressure loss and reduces pulse excitation through the bend design between the oil pump and the cooler. Simultaneously, by adjusting the bend angle through the amplitude difference, it achieves a synergistic improvement in lubrication performance and engine NVH targets.

[0114] This application also provides an engine.

[0115] The engine in this application embodiment includes the oil circuit system described in the above embodiment.

[0116] by Figure 2 For example, in the engine, the first pipe 3 and the second pipe 4 are arranged at an angle to form a curved pipe design. The oil pump 1 outputs oil to the cooler 2 through the curved pipe. The curved pipe design increases the pressure loss when the oil flows through, thereby reducing the pressure value of the pipe tap connected to the cooler. This can reduce the impact of the oil output by the oil pump 1 on the cooler 2, thereby reducing the vibration noise of the oil pan and achieving the purpose of reducing engine radiation noise and improving engine NVH performance.

[0117] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0118] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0119] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. An oil passage system characterized by comprising: include: Oil pump (1); Cooler (2), the cooler (2) has an oil inlet and an oil outlet, the oil outlet being connected to the main oil circuit; A first pipe (3) and a second pipe (4) are connected, with the first pipe (3) connected to the oil pump outlet of the oil pump (1) and the second pipe (4) connected to the oil inlet; wherein, The extension direction of the first pipeline (3) is at an angle to the extension direction of the second pipeline (4).

2. The oil passage system according to claim 1, characterized by The included angle is 90°-160°.

3. The oil passage system according to claim 1 or 2, characterized by Also includes: A buffer element (5) is disposed upstream of the oil inlet of the cooler (2) and is used to connect to the second pipeline (4).

4. The oil passage system according to claim 3, characterized by The buffer component (5) includes a buffer cavity (51), and a buffer inlet (52) and a buffer outlet (53) are respectively led out from two opposite side walls of the buffer cavity (51). The buffer inlet (52) is connected to the second pipeline (4), and the buffer outlet (53) is connected to the oil inlet hole. The flow diameter of the buffer outlet (53) is smaller than the flow diameter of the buffer inlet (52).

5. A method of designing an oil circuit system as claimed in any one of claims 1-4, characterized in that include: Construct the oil circuit connection model of the oil circuit system; Obtain the initial oil pressure amplitude of the oil circuit connection model, and calculate the amplitude difference between the initial oil pressure amplitude and the preset pressure amplitude; The included angle is adjusted based on the amplitude difference until the oil pan noise of the oil circuit connection model meets the preset noise attenuation condition, thereby generating at least one design parameter of the oil circuit system.

6. The method of claim 5, wherein, When the oil circuit system also includes a buffer, the included angle is adjusted based on the amplitude difference until the oil pan noise of the oil circuit connection model meets the preset noise attenuation condition, including: The angle adjustment range is determined based on the amplitude difference. The angle adjustment range is matched based on the target design parameters of the oil circuit system to obtain the target angle, and the included angle is adjusted according to the target angle. When the oil pan noise of the oil circuit connection model does not meet the preset noise attenuation condition, the cavity volume of the buffer is adjusted according to the oil pressure amplitude of the oil circuit connection model and the initial oil pressure amplitude until the oil pan noise meets the preset noise attenuation condition.

7. The method of claim 6, wherein, Determining the angle adjustment range based on the amplitude difference includes: Obtain the initial angle of the included angle, and determine the maximum allowable adjustment angle based on the initial angle; Obtain the preset oil viscosity and preset oil flow rate of the oil circuit system, and determine the correction angle based on the amplitude difference, the preset oil viscosity, and the preset oil flow rate; The maximum allowable adjustment angle is adjusted based on the correction angle to determine the angle adjustment range.

8. The method of claim 6, wherein, Adjusting the cavity volume of the buffer component according to the oil pressure amplitude of the oil circuit connection model includes: Obtain the actual amplitude difference between the oil pressure amplitude of the oil circuit connection model and the preset pressure amplitude; The target cavity cross-sectional area is determined based on the actual amplitude difference and the current cavity cross-sectional area of ​​the buffer, so as to adjust the cavity volume of the buffer according to the target cavity cross-sectional area.

9. The method according to any one of claims 5-8, characterized in that, The method further includes: extract a fluid flow region of the oil circuit connection model to construct a corresponding flow passage model; perform a fluid dynamics calculation on the flow passage model based on a preset boundary condition to obtain a pressure fluctuation excitation force; identify a corresponding oil pressure amplitude based on the pressure fluctuation excitation force and a target monitoring position; map the pressure fluctuation excitation force to a corresponding acoustic mesh of the flow passage model to obtain a corresponding oil sump noise.

10. An engine characterized by, An oil circuit system comprising any one of claims 1-4.

Images