Piston cooling nozzle and method of designing same

Abstract

The present application relates to the technical field of engine, and discloses a piston cooling nozzle and a design method thereof, wherein the cooling nozzle comprises a valve body, a first valve seat arranged on the valve body, a second valve seat arranged on the valve body, a first control valve arranged on the first valve seat, a second control valve arranged on the second valve seat, a first cooling nozzle arranged on the first valve seat and communicated with an inner cavity of the first valve seat, and a second cooling nozzle arranged on the second valve seat and communicated with an inner cavity of the second valve seat.The cooling nozzle of the present application can spray the oil jet of the cooling nozzle to different appropriate positions on the inner cavity surface of the piston, so that more positions of the piston can be cooled, the cooling effect is maximized, the thermal stress of the piston is reduced, the service life of the piston and the engine is prolonged, the cost is reduced, the thermal load of the combustion system is reduced, and the reliability of the whole vehicle is improved.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and in particular to a piston cooling nozzle and a design method for a piston cooling nozzle. Background Technology

[0002] During engine operation, the piston is subjected to high temperature and high pressure loads for extended periods due to the high temperatures generated by fuel combustion and mechanical friction. To ensure piston performance and extend its service life, effective piston cooling is necessary. Related technologies employ piston cooling nozzles to spray engine oil into the piston crown cavity, internal oil cooling passages, or piston skirt to achieve a cooling effect.

[0003] However, current piston cooling nozzle structures typically have some limitations. During the design process, pressure control is often achieved through a valve body integrated into the nozzle. When the oil pressure exceeds a set threshold, the valve opens, and the nozzle sprays oil to cool the piston. If the threshold is set too high, the piston cannot be adequately cooled, affecting its lifespan; if the threshold is set too low, oil waste occurs, impacting fuel economy. Uneven piston cooling or localized overcooling can lead to piston material fatigue, shortening the piston's lifespan. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, the first objective of this invention is to provide a piston cooling nozzle that, by spraying engine oil jets from the cooling nozzle onto different appropriate locations on the inner surface of the piston, allows for cooling of more areas of the piston, maximizing the cooling effect and further improving the uniformity of piston cooling. While simplifying the positioning design of the cooling nozzle, assembly accuracy can be effectively improved, minimizing the clearance requirements between the cooling nozzle and other parts. A compact design of the cooling nozzle is possible, suitable for engines of various cylinder diameters. This cooling nozzle structure has a fast response, providing more cooling flow when needed and reducing cooling flow when not needed, thereby improving cooling efficiency. By improving the uniformity of piston cooling, the thermal stress on the piston is reduced, extending the service life of the piston and engine, reducing costs, lowering the thermal load on the combustion system, and improving overall vehicle reliability.

[0005] The second objective of this invention is to provide a design method for a piston cooling nozzle.

[0006] To achieve the above objectives, a first aspect of the present invention provides a piston cooling nozzle, comprising: a valve body; a first valve seat disposed on the valve body; a second valve seat disposed on the valve body; a first control valve disposed on the first valve seat, the inner cavity of the first control valve selectively communicating with the inner cavity of the first valve seat, and the inner cavity of the first valve seat communicating with an oil passage of a target engine cylinder; the first control valve being configured to perform an opening or closing action based on the oil pressure of the target engine cylinder; and a second control valve disposed on the second valve seat. The inner cavity of the control valve is selectively connected to the inner cavity of the second valve seat, and the inner cavity of the second valve seat is connected to the oil passage of the target engine block; the second control valve is configured to open or close according to the oil pressure and oil temperature of the target engine block; a first cooling nozzle is disposed on the first valve seat and connected to the inner cavity of the first valve seat, and the first cooling nozzle is used to cool the first load area of ​​the target piston; a second cooling nozzle is disposed on the second valve seat and connected to the inner cavity of the second valve seat, and the second cooling nozzle is used to cool the second load area of ​​the target piston.

[0007] In addition, the piston cooling nozzle according to the above embodiments of the present invention may also have the following additional technical features:

[0008] According to some embodiments of the present invention, the valve body is provided with a first limiting hole, and the first valve seat passes through the first limiting hole and is fixedly disposed on the valve body.

[0009] According to some embodiments of the present invention, the valve body is provided with a second limiting hole, and the second valve seat passes through the second limiting hole and is fixedly mounted on the valve body.

[0010] According to some embodiments of the present invention, the inner contour of the first valve seat is provided with an internal thread structure, the outer contour of the first control valve is provided with an external thread structure, the first control valve passes through the first valve seat and is fixed on the first valve seat by the external thread structure cooperating with the internal thread structure of the first valve seat; the first control valve cooperates with the first preset through hole of the target engine cylinder block through the internal thread structure, so that the inner cavity of the first control valve is connected to the oil passage of the target engine cylinder block through the first preset through hole.

[0011] According to some embodiments of the present invention, the bottom of the second control valve engages with the second preset through hole of the target engine cylinder block, so that the inner cavity of the second control valve communicates with the oil passage of the target engine cylinder block through the second preset through hole.

[0012] According to some embodiments of the present invention, a sealing ring is provided at the connection between the second valve seat and the oil passage of the target engine cylinder.

[0013] According to some embodiments of the present invention, the first control valve includes a first sealing cover, a first pressure spring, and a first plunger; one end of the first pressure spring is connected to the first sealing cover, and the other end of the first pressure spring is connected to the first plunger; the first plunger is used to generate a force on the first pressure spring under the action of the oil pressure of the target engine cylinder, so as to compress the first pressure spring and drive the first plunger to move in the compression direction of the first pressure spring, so as to control the communication state between the inner cavity of the first control valve and the oil passage of the target engine cylinder.

[0014] According to some embodiments of the present invention, the second control valve includes a second sealing cover, a thermo-pressure spring assembly, and a second plunger; the thermo-pressure spring assembly includes a second pressure spring and a temperature control spring; one end of the thermo-pressure spring assembly is connected to the second sealing cover, and the other end of the thermo-pressure spring assembly is connected to the second plunger; the second plunger is used to generate a force on the second pressure spring under the action of the oil pressure of the target engine cylinder, so as to compress the second pressure spring and drive the second plunger to move in the compression direction of the second pressure spring, so as to control the communication state between the inner cavity of the second control valve and the oil passage of the target engine cylinder; and / or, the temperature control spring is used to generate a compression amount under the action of the oil temperature of the target engine cylinder, so as to drive the second plunger to move in the compression direction of the temperature control spring, so as to control the communication state between the inner cavity of the second control valve and the oil passage of the target engine cylinder.

[0015] A piston cooling nozzle according to an embodiment of the present invention includes: a valve body; a first valve seat disposed on the valve body; a second valve seat disposed on the valve body; a first control valve disposed on the first valve seat, the inner cavity of the first control valve selectively communicating with the inner cavity of the first valve seat, and the inner cavity of the first valve seat communicating with an oil passage of a target engine cylinder; the first control valve is configured to perform an opening or closing action based on the oil pressure of the target engine cylinder; a second control valve disposed on the second valve seat, the inner cavity of the second control valve selectively communicating with the inner cavity of the second valve seat, and the inner cavity of the second valve seat communicating with an oil passage of the target engine cylinder; the second control valve is configured to perform an opening or closing action based on the oil pressure and oil temperature of the target engine cylinder; a first cooling nozzle disposed on the first valve seat and communicating with the inner cavity of the first valve seat, the first cooling nozzle being used to cool a first load area of ​​the target piston; and a second cooling nozzle disposed on the second valve seat and communicating with the inner cavity of the second valve seat, the second cooling nozzle being used to cool a second load area of ​​the target piston. Therefore, this cooling nozzle sprays engine oil jets onto different appropriate locations on the piston's inner surface, allowing more areas of the piston to be cooled, thus maximizing the cooling effect and further improving the uniformity of piston cooling. By simplifying the cooling nozzle's positioning design, assembly precision can be effectively improved, minimizing the clearance requirements between the cooling nozzle and other parts. A compact design of the cooling nozzle is possible, suitable for engines of various cylinder diameters. This cooling nozzle structure has a fast response, providing more cooling flow when needed and reducing cooling flow when not needed, thereby improving cooling efficiency. By improving the uniformity of piston cooling, it reduces piston thermal stress, extends the service life of the piston and engine, reduces costs, lowers the thermal load on the combustion system, and improves overall vehicle reliability.

[0016] The second objective of this invention is to propose a design method for piston cooling nozzles. By combining the actual operating conditions of the entire machine, the method determines whether the piston cooling nozzles are working. When the piston cooling nozzles are working, the method precisely controls the direction and amount of oil injection. At the same time, it minimizes the demand on the oil pump capacity from the cooling system level, reduces energy waste, thereby further improving fuel economy and increasing the overall thermal efficiency of the machine. This effectively reduces the deviations that may occur in experience-based designs and improves design efficiency.

[0017] To achieve the above objectives, a second aspect of the present invention provides a method for designing a piston cooling nozzle, comprising: determining a first load zone and a second load zone for cooling a target piston; determining a first spray angle of a first cooling nozzle based on the position of the first load zone; determining a second spray angle of a second cooling nozzle based on the position of the second load zone; determining a first rated flow rate of a first control valve and a second rated flow rate of a second control valve based on the highest operating temperature of the target piston; determining a first orifice diameter of the first cooling nozzle based on the first rated flow rate and the average linear velocity of the target piston; determining a second orifice diameter of the second cooling nozzle based on the second rated flow rate and the average linear velocity of the target piston; and determining a first opening pressure threshold of the first control valve and a second opening pressure threshold of the second control valve based on the oil pressure curve and oil temperature curve of the target engine block. The system determines the opening pressure threshold; based on the first opening pressure threshold, it determines the first preload and first spring stiffness of the first pressure spring in the first control valve; based on the second opening pressure threshold, it determines the second preload and second spring stiffness of the second pressure spring in the second control valve; based on the second opening pressure threshold, it determines the third preload and third spring stiffness of the temperature control spring in the second control valve; based on the first injection angle, first orifice diameter, first opening pressure threshold, first preload, and first spring stiffness, it determines the first design parameters of the first control valve and the first cooling nozzle; based on the second injection angle, second orifice diameter, second opening pressure threshold, second preload, second spring stiffness, third preload, and third spring stiffness, it determines the second design parameters of the second control valve and the second cooling nozzle; based on the first and second design parameters, it designs the piston cooling nozzle.

[0018] In addition, the piston cooling nozzle design method according to the above embodiments of the present invention may also have the following additional technical features:

[0019] According to some embodiments of the present invention, determining a first load zone and a second load zone for cooling a target piston includes: establishing a finite element model of the target piston and piston cooling nozzle based on the operating conditions of the target engine and the structural parameters of the target engine cylinder block; determining the temperature field distribution of the target piston based on the finite element model; and determining the first load zone and the second load zone of the target piston based on the temperature field distribution.

[0020] According to the piston cooling nozzle design method of the present invention, a first load zone and a second load zone for cooling a target piston are determined, and a first spray angle of the first cooling nozzle is determined based on the position of the first load zone, and a second spray angle of the second cooling nozzle is determined based on the position of the second load zone; a first rated flow rate of the first control valve and a second rated flow rate of the second control valve are determined based on the highest operating temperature of the target piston, a first orifice diameter of the first cooling nozzle is determined based on the first rated flow rate and the average linear velocity of the target piston, and a second orifice diameter of the second cooling nozzle is determined based on the second rated flow rate and the average linear velocity of the target piston; a first opening pressure threshold of the first control valve and a second opening pressure threshold of the second control valve are determined based on the oil pressure curve and oil temperature curve of the target engine block; and based on... The first opening pressure threshold determines the first preload and first spring stiffness of the first pressure spring in the first control valve. The second opening pressure threshold determines the second preload and second spring stiffness of the second pressure spring in the second control valve. The second opening pressure threshold also determines the third preload and third spring stiffness of the temperature control spring in the second control valve. The first design parameters for the first control valve and the first cooling nozzle are determined based on the first injection angle, the first orifice diameter, the first opening pressure threshold, the first preload, and the first spring stiffness. The second design parameters for the second control valve and the second cooling nozzle are determined based on the second injection angle, the second orifice diameter, the second opening pressure threshold, the second preload, the second spring stiffness, the third preload, and the third spring stiffness. The piston cooling nozzle is designed based on the first and second design parameters. Therefore, this method determines whether the piston cooling nozzle is working by combining the actual operating conditions of the whole machine, and precisely controls the direction and amount of oil injection when the piston cooling nozzle is working. At the same time, it minimizes the demand on the oil pump capacity from the cooling system level, reduces energy waste, thereby further improving fuel economy, further improving the thermal efficiency of the whole machine, effectively reducing the deviation that may be caused by experience-based design, and improving design efficiency.

[0021] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a piston cooling nozzle according to some embodiments of the present invention;

[0023] Figure 2 This is a top view of a piston cooling nozzle according to some embodiments of the present invention;

[0024] Figure 3 This is a cross-sectional view of a piston cooling nozzle according to some embodiments of the present invention;

[0025] Figure 4 A flowchart illustrating a design method for a piston cooling nozzle according to some embodiments of the present invention;

[0026] Figure 5 This is a flowchart illustrating a design method for a piston cooling nozzle according to other embodiments of the present invention.

[0027] Explanation of reference numerals in the attached figures

[0028] Valve body 1, first control valve 2, first sealing cover 21, first pressure spring 22, first plunger 23, second control valve 3, second sealing cover 31, valve plate 32, second plunger 33, second pressure spring 34, temperature control spring 35, sealing ring 4, first cooling nozzle 5, second cooling nozzle 6, first valve seat 7 and second valve seat 8. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0030] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this invention should have the ordinary meaning understood by those skilled in the art. The terms "first," "second," and similar terms used in the embodiments of this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0031] As described in the background section, during engine operation, the piston is subjected to high temperature and high pressure loads for extended periods due to the high temperatures generated by fuel combustion and mechanical friction. To ensure piston performance and extend its service life, effective cooling of the piston is necessary. Related technologies employ piston cooling nozzles to spray engine oil into the piston top cavity, internal oil cooling passages, or piston skirt to achieve a cooling effect.

[0032] In the process of developing this invention, the applicant discovered that current piston cooling nozzle structures typically have some limitations. In the design of cooling nozzles, pressure control is often achieved through a valve body integrated into the nozzle. When the oil pressure exceeds a set threshold, the valve opens, and the cooling nozzle sprays oil to cool the piston. If the threshold is set too high, the piston cannot be adequately cooled, affecting its lifespan; if the threshold is set too low, it leads to oil waste and affects fuel economy. Uneven piston cooling or localized overcooling can cause piston material fatigue, shortening the piston's service life.

[0033] In related technologies, electronic control units are used to regulate the opening and closing of the piston cooling nozzles to adapt to different operating conditions. However, this structure typically requires additional electrically controlled nozzle valves, increasing system complexity and cost. Multi-nozzle nozzles are also used to achieve more uniform cooling, but they are less effective in intelligent adjustment and adaptive control.

[0034] The design method of the piston cooling nozzle and the piston cooling nozzle proposed in the embodiments of the present invention are described below with reference to the accompanying drawings.

[0035] refer to Figure 1 This is a schematic diagram of a piston cooling nozzle according to some embodiments of the present invention.

[0036] The piston cooling nozzle of the present invention includes a valve body 1, a first valve seat 7, a second valve seat 8, a first control valve 2, a second control valve 3, a sealing ring 4, a first cooling nozzle 5, and a second cooling nozzle 6.

[0037] refer to Figure 2 The figure shows a top view of a piston cooling nozzle according to some embodiments of the present invention. The valve body 1 is provided with a first limiting hole (not shown in the figure), and a first valve seat 7 passes through the first limiting hole and is fixedly mounted on the valve body 1. By providing the first limiting hole, safety can be improved, control accuracy enhanced, automatic control saves manpower, mechanical stability and reliability improved, debugging and maintenance facilitated, and product durability increased.

[0038] The first cooling nozzle 5 is disposed on the first valve seat 7 and communicates with the inner cavity of the first valve seat 7. The first cooling nozzle 5 is used to cool the first load area of ​​the target piston. By spraying the oil jet from the first cooling nozzle 5 onto appropriate positions on the inner surface of the piston, more parts of the piston can be cooled, thereby maximizing the cooling effect and further improving the uniformity of piston cooling.

[0039] The first control valve 2 is disposed on the first valve seat 7. The inner cavity of the first control valve 2 is selectively connected to the inner cavity of the first valve seat 7. The inner cavity of the first valve seat 7 is connected to the oil passage of the target engine cylinder. The first control valve 2 is used to perform opening or closing actions according to the oil pressure of the target engine cylinder.

[0040] In some embodiments, the positioning between the first valve seat 7 and the target engine cylinder block can adopt other positioning methods, such as a combination of cylindrical pin + diamond pin or positioning ring + bolt, as long as precise positioning can be achieved through the external structure of the two control valves.

[0041] The inner contour of the first valve seat 7 is provided with an internal thread structure, and the outer contour of the first control valve 2 is provided with an external thread structure. The first control valve 2 passes through the first valve seat 7 and is fixed on the first valve seat 7 by cooperating with the internal thread structure of the first valve seat 7 through the external thread structure. The first control valve 2 cooperates with the first preset through hole of the target engine cylinder block through the internal thread structure, so that the inner cavity of the first control valve 2 is connected to the oil passage of the target engine cylinder block through the first preset through hole.

[0042] refer to Figure 3 The diagram shows a cross-sectional view of a piston cooling nozzle according to some embodiments of the present invention. The first control valve 2 includes a first sealing cover plate 21, a first pressure spring 22, and a first plunger 23. The first sealing cover plate 21 can be a plugging cover plate, and the first plunger 23 can be replaced with a ball valve structure. One end of the first pressure spring 22 is connected to the first sealing cover plate 21, and the other end is connected to the first plunger 23. The first plunger 23 is used to exert a force on the first pressure spring 22 under the action of the oil pressure in the target engine cylinder, causing the first pressure spring 22 to compress and drive the first plunger 23 to move in the compression direction of the first pressure spring 22, thereby controlling the communication between the inner cavity of the first control valve 2 and the oil passage of the target engine cylinder.

[0043] It should be explained that the first plunger 23 has a fast response speed and can provide a large flow rate.

[0044] Continue to refer to Figure 2 The valve body 1 is provided with a second limiting hole (not shown in the figure), and the second valve seat 8 passes through the second limiting hole and is fixedly mounted on the valve body 1. By providing the second limiting hole, safety can be improved, control accuracy can be enhanced, automatic control can save manpower, mechanical stability and reliability can be improved, debugging and maintenance can be facilitated, and product durability can be improved.

[0045] The second cooling nozzle 6 is disposed on the second valve seat 8 and communicates with the inner cavity of the second valve seat 8. The second cooling nozzle 6 is used to cool the second load zone of the target piston. By spraying the oil jet from the second cooling nozzle 6 onto appropriate positions on the inner surface of the piston, more parts of the piston can be cooled, thereby maximizing the cooling effect and further improving the uniformity of piston cooling.

[0046] The second control valve 3 is disposed on the second valve seat 8. The inner cavity of the second control valve 3 is selectively connected to the inner cavity of the second valve seat 8. The inner cavity of the second valve seat 8 is connected to the oil passage of the target engine cylinder. The second control valve 3 is used to perform opening or closing actions according to the oil pressure and oil temperature of the target engine cylinder.

[0047] In some embodiments, the positioning between the second valve seat 8 and the target engine cylinder block can adopt other positioning methods, such as a combination of cylindrical pin + diamond pin or positioning ring + bolt, as long as precise positioning can be achieved through the external structure of the two control valves.

[0048] The bottom of the second control valve 3 engages with the second preset through hole of the target engine cylinder block, so that the inner cavity of the second control valve 3 is connected to the oil passage of the target engine cylinder block through the second preset through hole.

[0049] It should be explained that current control valves and valve bodies are typically positioned using locating pins. These locating pins include conical locating pins, cylindrical locating pins, and threaded locating pins, each achieving precise positioning through different structural features and functional applications. For example, conical locating pins are suitable for applications subject to radial and axial loads, while cylindrical locating pins are suitable for applications requiring frequent disassembly and assembly. However, due to the clearance between the locating pin and the locating hole, the clearance value for each workpiece during positioning is highly variable, which can affect the stability of workpiece machining quality. During use, locating pins may lose positioning accuracy due to wear or deformation, requiring regular inspection and maintenance. Furthermore, due to factors such as movement and vibration, some positioning components may loosen or deform, leading to positioning failure.

[0050] However, the second control valve 3 of this invention is integrally installed with the valve body 1 (welded or press-fitted). The mounting hole of the second control valve 3 on the target engine cylinder block is a pin / hole precision fit (such as clearance fit), which allows the cooling nozzle and the cylinder block to achieve a high-precision fit, making the nozzle position more accurate, thereby improving the accuracy of oil injection from the cooling nozzle. Under the premise of simplifying the positioning design of the cooling nozzle, it can effectively improve the assembly accuracy and minimize the clearance requirements between the cooling nozzle and other parts. Among them, hole precision fit usually refers to the tight fit relationship between the hole and the shaft in mechanical design. This fit relationship is determined by the relationship between the tolerance zones of the hole and the shaft. It can determine the tightness of the fit. When the algebraic difference between the hole size and the mating shaft size is positive, it is called clearance; when it is negative, it is called interference. According to the sign and magnitude of this algebraic difference, the fit can be divided into three basic types: clearance fit, interference fit, and transition fit.

[0051] A sealing ring 4 is provided at the connection between the second valve seat 8 and the oil passage of the target engine cylinder. The sealing ring 4 can be an elastic rubber ring structure. The sealing ring 4 can achieve a seal with the cylinder mounting hole, effectively reducing the amount of oil leakage.

[0052] The second control valve 3 includes a second sealing cover 31, a valve plate 32, a temperature and pressure spring assembly, and a second plunger 33. The second sealing cover 31 can be a blocking cover, and the temperature and pressure spring assembly includes a second pressure spring 34 and a temperature control spring 35.

[0053] One end of the thermo-pressure spring assembly is connected to the second sealing cover plate 31, and the other end of the thermo-pressure spring assembly is connected to the second plunger 33. The second plunger 33 is used to generate force on the second pressure spring 34 under the action of the oil pressure of the target engine cylinder, so as to compress the second pressure spring 34 and drive the second plunger 33 to move in the compression direction of the second pressure spring 34, so as to control the communication state between the inner cavity of the second control valve 3 and the oil passage of the target engine cylinder. The thermo-pressure spring 35 is used to generate compression under the action of the oil temperature of the target engine cylinder, so as to drive the second plunger 33 to move in the compression direction of the thermo-pressure spring 35, so as to control the communication state between the inner cavity of the second control valve 3 and the oil passage of the target engine cylinder. The flow rate of the second cooling nozzle 6 is automatically adjusted by the temperature control spring 35 to respond in a timely manner to changes in engine oil temperature. The return spring can accurately reset the valve plate 32 when the temperature returns to normal. At the same time, when the oil pressure increases, it pushes the second control valve 3 to open. By using the combination of the temperature control spring 35 and the second pressure spring 34, the internal structure of the valve body can be greatly simplified, and the response speed of the valve body opening and closing can be improved to a certain extent.

[0054] Alternatively, the temperature control spring 35 drives the second plunger 33 to move in the compression direction of the second pressure spring 34 to control the communication state between the inner cavity of the second control valve 3 and the oil passage of the target engine cylinder.

[0055] Alternatively, the temperature control spring 35 is used to generate compression under the action of the oil temperature of the target engine cylinder, driving the second plunger 33 to move in the compression direction of the temperature control spring 35, so as to control the communication state between the inner cavity of the second control valve 3 and the oil passage of the target engine cylinder.

[0056] The temperature control spring 35 is made of shape memory alloy, possessing a suitable phase change temperature range and mechanical properties. When the temperature rises, the temperature control spring 35 expands due to heat, pushing the valve plate 32 upwards and opening the nozzle. The second pressure spring 34, located above the valve plate 32 on the opposite side of the temperature control spring 35, is used to push the temperature control spring 35 back to its original position and close the second cooling nozzle 6 when cooling demand decreases. Simultaneously, when the oil pressure increases, the valve plate 32 also moves upwards, compressing the second pressure spring 34. At this time, the second cooling nozzle 6 also opens. The temperature control spring 35 automatically adjusts the cooling medium flow rate, achieving an energy-saving and efficient cooling effect.

[0057] In some embodiments, when the oil pressure in the main oil passage increases, the first plunger 23 inside the first control valve 2 is forced upward to compress the first pressure spring 22 inside the first control valve 2, so that the first control valve 2 is in the open state. At this time, the oil can be sprayed through the first cooling nozzle 5 to the corresponding position of the set piston cavity to cool the piston.

[0058] When the oil temperature is lower than the set value and the main oil passage oil pressure is lower than the set value, the elastic force of the temperature control spring 35 is weak, and the oil pressure in the main oil passage is not enough to push the second pressure spring 34 to compress. At this time, the second control valve 3 is in the closed state.

[0059] When the oil temperature is higher than the set value, but the oil pressure in the main oil passage is lower than the set value, although the oil pressure in the main oil passage is insufficient to compress the second pressure spring 34, the elastic force of the temperature control spring 35 increases and pushes the valve plate 32 upward. At this time, the second control valve 3 is in the open state, and the oil can be sprayed through the second cooling nozzle 6 to the corresponding position in the set piston cavity to cool the piston.

[0060] When the oil temperature is lower than the set value, but the main oil passage oil pressure is higher than the set value, although the elasticity of the temperature control spring 35 is weak, the oil pressure in the main oil passage will push the valve plate 32 to compress the second pressure spring 34. At this time, the second control valve 3 is in the open state, and the oil can be sprayed through the second cooling nozzle 6 to the corresponding position of the set piston cavity to cool the piston.

[0061] When the oil temperature is higher than the set value and the main oil passage oil pressure is higher than the set value, the elastic force of the temperature control spring 35 increases and pushes the valve plate 32 upward. At the same time, the oil pressure in the main oil passage will push the valve plate 32 to compress the second pressure spring 34. At this time, the second control valve 3 is in the open state, and the oil can be sprayed through the second cooling nozzle 6 to the corresponding position of the set piston cavity to cool the piston.

[0062] Therefore, the first control valve 2 of the present invention can be opened or closed according to the set oil pressure to cool the main heat load area of ​​the piston. When the load increases further, or the engine speed is low but the oil temperature is high, it is necessary to supplement the cooling of the second load area of ​​the piston. At this time, the second control valve 3 opens, so that the two cooling nozzles work in parallel. The flow rate of the cooling nozzles can be adjusted independently or collaboratively as needed to achieve a compact design of the cooling nozzles, which is suitable for engines of various cylinder diameters. The first control valve 2 and the second control valve 3 (in addition to the valve body function) also have a positioning function. Under the premise of simplifying the nozzle positioning design, the assembly accuracy can be effectively improved, the gap requirement between the cooling nozzle and other parts can be minimized, the heat load of the combustion system can be effectively reduced, and the reliability of the whole vehicle can be improved.

[0063] In summary, the piston cooling nozzle according to an embodiment of the present invention includes: a valve body; a first valve seat disposed on the valve body; a second valve seat disposed on the valve body; a first control valve disposed on the first valve seat, the inner cavity of the first control valve selectively communicating with the inner cavity of the first valve seat, and the inner cavity of the first valve seat communicating with the oil passage of the target engine cylinder; the first control valve is configured to perform an opening or closing action according to the oil pressure of the target engine cylinder; a second control valve disposed on the second valve seat, the inner cavity of the second control valve selectively communicating with the inner cavity of the second valve seat, and the inner cavity of the second valve seat communicating with the oil passage of the target engine cylinder; the second control valve is configured to perform an opening or closing action according to the oil pressure and oil temperature of the target engine cylinder; a first cooling nozzle disposed on the first valve seat and communicating with the inner cavity of the first valve seat, the first cooling nozzle being used to cool a first load area of ​​the target piston; and a second cooling nozzle disposed on the second valve seat and communicating with the inner cavity of the second valve seat, the second cooling nozzle being used to cool a second load area of ​​the target piston. Therefore, this cooling nozzle sprays engine oil jets onto different appropriate locations on the piston's inner surface, allowing more areas of the piston to be cooled, thus maximizing the cooling effect and further improving the uniformity of piston cooling. By simplifying the cooling nozzle's positioning design, assembly precision can be effectively improved, minimizing the clearance requirements between the cooling nozzle and other parts. A compact design of the cooling nozzle is possible, suitable for engines of various cylinder diameters. This cooling nozzle structure has a fast response, providing more cooling flow when needed and reducing cooling flow when not needed, thereby improving cooling efficiency. By improving the uniformity of piston cooling, it reduces piston thermal stress, extends the service life of the piston and engine, reduces costs, lowers the thermal load on the combustion system, and improves overall vehicle reliability.

[0064] refer to Figure 4 This is a flowchart of a piston cooling nozzle design method according to some embodiments of the present invention.

[0065] like Figure 4 As shown, the design method of the piston cooling nozzle in this embodiment of the invention may include the following steps:

[0066] S401, determine the first load zone and the second load zone for cooling the target piston, and determine the first spray angle of the first cooling nozzle based on the position of the first load zone, and determine the second spray angle of the second cooling nozzle based on the position of the second load zone.

[0067] Specifically, since the piston is one of the core components in the engine, it needs to withstand the huge thermal and mechanical loads brought about by high temperature, high pressure and high speed reciprocating motion. Therefore, in order to ensure that the piston can work normally under such conditions, it is crucial to cool it effectively.

[0068] To determine the load zone for cooling the piston, a finite element model of the piston and cooling nozzles needs to be established first. The first step is model creation: using professional modeling software (such as SolidWorks, ProE, etc.), a 3D model of the piston and cooling nozzles is created. This model needs to accurately reflect the piston's geometry and structural characteristics, including key parts such as the piston top surface, skirt, and pin holes, as well as the location and shape of the cooling oil passages and nozzles. The second step is mesh generation: in finite element analysis software (such as ANSYS, ABAQUS, etc.), the piston model is meshed. The mesh density and size affect the accuracy of the analysis and the calculation time, so they need to be chosen appropriately. For areas with large temperature gradients, such as the piston top and annular groove region, local mesh refinement should be performed to improve calculation accuracy. The third step is material property definition: based on the piston material (usually aluminum alloy), its thermophysical properties, such as density, specific heat capacity, thermal conductivity, and coefficient of thermal expansion, are defined in the finite element software. The fourth step is boundary conditions and load application: setting the thermal boundary conditions of the piston during operation, including the surface temperature of the piston in contact with the combustion gas and the heat transfer coefficient of the piston in contact with the coolant. Simultaneously, based on the engine's operating conditions, thermal and mechanical loads are applied to the piston. The fifth step is temperature field calculation: finite element thermal analysis is performed to obtain the piston's temperature field distribution. This will show the temperature changes of various parts of the piston under operating conditions. The sixth step is result analysis: the calculation results are analyzed to identify the areas with the highest temperatures on the piston; these areas are typically the load zones most in need of cooling. For example, the piston top, annular groove area, and near the pin hole are usually areas with the highest thermal load. The seventh step is cooling strategy optimization: based on the temperature field distribution results, the cooling locations corresponding to valve body 1 and valve body 2 are initially determined. This may involve adjusting the design of the cooling oil passages, changing the fuel injection strategy, or adding additional cooling measures. The eighth step is verification and iteration: it may be necessary to verify the finite element analysis results through experimental testing (such as the hardness plug method) and iteratively optimize the model based on the experimental data to ensure the accuracy of the analysis results. Through the above steps, the first and second load zones for cooling the target piston can be systematically determined.

[0069] After obtaining the first and second load zones, the design requirements for the nozzles are determined based on the piston's temperature field distribution. This includes the number, position, and spray angle of the nozzles. The nozzle design must ensure that the coolant can cover the hot spots on the piston. The spray angle is determined based on the piston geometry and the location of the hot spots. Ideally, the spray angle should allow the coolant to directly impact the hottest area of ​​the piston. The nozzle's spray performance includes jet velocity distribution, jet boundary, and jet flow rate distribution, all of which affect the cooling effect. For example, these parameters can be studied by establishing theoretical models and using simulation software (such as FLUENT). The results of theoretical models and simulation analyses need to be verified through experimental testing. Experimental setups can be designed to test the cooling effect under different spray angles and optimize accordingly. The nozzle arrangement also affects the cooling effect. For example, a square arrangement may provide the best water distribution uniformity, while a triangular or hexagonal arrangement may be more economical in some cases. In actual operation, the engine's actual operating conditions, such as oil pressure and nozzle flow coefficient, need to be considered, as these all affect nozzle performance. The flow distribution and impact force of the nozzle are important factors affecting the cooling effect. It is necessary to ensure that the nozzle can provide sufficient impact force to cover the target area while maintaining the uniformity of flow distribution.

[0070] Therefore, it is necessary to determine the first injection angle of the first cooling nozzle based on the location of the first load zone, and the second injection angle of the second cooling nozzle based on the location of the second load zone, in order to ensure that the piston is effectively cooled, thereby improving the performance and reliability of the engine.

[0071] S402, determine the first rated flow rate of the first control valve and the second rated flow rate of the second control valve according to the highest operating temperature of the target piston, determine the first diameter of the first cooling nozzle according to the first rated flow rate and the average linear velocity of the target piston, and determine the second diameter of the second cooling nozzle according to the second rated flow rate and the average linear velocity of the target piston.

[0072] Specifically, the first rated flow rate of the first control valve and the second rated flow rate of the second control valve are determined based on the target piston's highest operating temperature and calculated flow rate, pressure difference, and flow coefficient. After determining the rated flow rates of the control valves, the oil injection speed of the cooling nozzles is determined based on the average linear velocity of the target piston. The first diameter (first cross-sectional area) of the first cooling nozzle needs to be determined based on the first rated flow rate and the average linear velocity of the target piston, and the second diameter (second cross-sectional area) of the second cooling nozzle needs to be determined based on the second rated flow rate and the average linear velocity of the target piston. The nozzle diameter directly affects the coolant flow rate and thus the cooling effect. To determine the nozzle diameter, a flow rate calculator can be used to determine the flow rate at a given operating pressure, or a spray coverage calculator can be used to determine the spray coverage area at a given spray height and angle. These tools can help select the correct nozzle size, spray angle, and number of nozzles to provide the desired cooling effect.

[0073] It should be noted that when selecting a nozzle, the flow rate, spray angle, spray pattern, and the sprayed medium must be considered. For example, the nozzle specification model may include connection size, flow rate, angle, and spray pattern code, such as 3 / 4PZ105180QZ, which indicates a 3 / 4-inch connection size, a flow rate of 10.5 liters per minute, a 180-degree angle, and a solid cone nozzle spray pattern.

[0074] S403, determine the first opening pressure threshold of the first control valve and the second opening pressure threshold of the second control valve based on the oil pressure curve and oil temperature curve of the target engine block.

[0075] Specifically, based on the oil pressure curve of the target engine block, the oil pressure changes under different operating conditions can be determined. This includes the peak and trough values ​​of the oil pressure, as well as fluctuations at different speeds and loads. Oil pressure testing typically includes monitoring oil pressure tests, low-speed oil pressure tests, and high-speed oil pressure tests to ensure that the oil pump can continuously provide sufficient pressure to guarantee adequate lubrication between the relatively moving parts inside the engine. The oil temperature curve shows the temperature changes of the oil under different operating conditions. Oil viscosity is inversely proportional to temperature; therefore, an increase in oil temperature will lead to a decrease in viscosity, affecting its lubricating performance. Temperature compensation is needed to adjust the oil pressure to ensure that appropriate pressure is maintained at different temperatures. The piston cooling requirements are closely related to the engine's thermal load. High-load areas typically require more cooling to prevent piston overheating. In high-load areas, the control valve needs to open at a lower pressure to increase coolant flow. The opening pressure threshold of the control valve should also consider the safety and reliability of the system. Excessively high opening pressure may cause the system to fail to respond promptly when cooling is needed, while excessively low opening pressure may cause the system to waste energy unnecessarily.

[0076] Through experimental testing and simulation analysis, the opening pressure threshold of the control valve can be determined more accurately. Therefore, the first opening pressure threshold of the first control valve and the second opening pressure threshold of the second control valve can be determined based on the oil pressure curve and oil temperature curve of the target engine block.

[0077] S404, determine the first preload and first spring stiffness of the first pressure spring in the first control valve according to the first opening pressure threshold, determine the second preload and second spring stiffness of the second pressure spring in the second control valve according to the second opening pressure threshold, and determine the third preload and third spring stiffness of the temperature control spring in the second control valve according to the second opening pressure threshold.

[0078] Specifically, after obtaining the first opening pressure threshold and the second opening pressure threshold, the first preload and the first spring stiffness of the first pressure spring in the first control valve can be determined based on the force corresponding to the first opening pressure threshold and the displacement of the valve core under the action of the force. The second preload and the second spring stiffness of the second pressure spring in the second control valve can be determined based on the force corresponding to the second opening pressure threshold and the displacement of the valve core under the action of the force. The third preload and the third spring stiffness of the temperature control spring in the second control valve can be determined based on the force corresponding to the second opening pressure threshold and the displacement of the valve core under the action of the force.

[0079] S405, determine the first design parameters of the first control valve and the first cooling nozzle based on the first injection angle, the first orifice diameter, the first opening pressure threshold, the first preload, and the first spring stiffness.

[0080] S406, determine the second design parameters of the second control valve and the second cooling nozzle based on the second injection angle, the second orifice diameter, the second opening pressure threshold, the second preload, the second spring stiffness, the third preload, and the third spring stiffness.

[0081] Specifically, the spray angle determines the coolant coverage and direction, which is crucial for ensuring effective cooling of the piston interior. The choice of spray angle should be based on the piston design and cooling requirements to ensure the coolant reaches the piston's critical hot zones. The spray angle is typically set by adjusting the nozzle geometry. The nozzle diameter directly affects the coolant flow rate and velocity. Larger diameters generally result in higher flow rates but may also increase pumping costs. Choosing an appropriate diameter balances cooling effectiveness and system efficiency.

[0082] The opening pressure threshold of a control valve is a key parameter determining when the valve begins to open to allow fluid flow. This value should be set according to the system's operating conditions and safety requirements. For example, in the design of a fuel tank safety valve in an automobile, the opening pressure is typically set at around 0.69 MPa to ensure that the internal pressure of the fuel tank remains within a controllable range. The preload of the pressure spring within the control valve determines the initial tension of the valve core when no external force is applied. The magnitude of the preload affects the opening pressure and sealing performance of the control valve. The preload can be adjusted by adjusting the spring compression or by selecting springs of different stiffnesses. Spring stiffness affects the response speed and flow characteristics of the control valve. A more stiff spring can provide a faster response but may also cause the control valve to become overly sensitive. The selection of spring stiffness should be based on the system's control requirements and operating pressure. Therefore, the first design parameters for the first control valve and the first cooling nozzle are determined based on the first injection angle, the first orifice diameter, the first opening pressure threshold, the first preload, and the first spring stiffness. The second design parameters of the second control valve and the second cooling nozzle are determined based on the second injection angle, the second orifice diameter, the second opening pressure threshold, the second preload, the second spring stiffness, the third preload, and the third spring stiffness.

[0083] S407, design the piston cooling nozzle according to the first design parameters and the second design parameters.

[0084] Specifically, after obtaining the first and second design parameters, the piston cooling nozzle is designed based on these parameters, and pressure tests, target tests, and flow tests are conducted to verify the accuracy of the design. If the design meets the design requirements, the individual components of the piston cooling nozzle assembly are further designed in detail to obtain the piston cooling nozzle assembly system, thus completing the piston cooling nozzle design. If the design does not meet the design requirements, the entire system needs to be re-simulated and analyzed to redetermine the first and second load zones for cooling the target piston, and the structural parameters of the piston cooling nozzle assembly are re-evaluated.

[0085] In some embodiments of the present invention, determining a first load zone and a second load zone for cooling the target piston includes: establishing a finite element model of the target piston and piston cooling nozzle based on the operating conditions of the target engine and the structural parameters of the target engine cylinder block; determining the temperature field distribution of the target piston based on the finite element model; and determining the first load zone and the second load zone of the target piston based on the temperature field distribution.

[0086] Specifically, the operating conditions of the target engine (e.g., idling, low load, medium load, high load / full load, acceleration) and the structural parameters of the target engine block (e.g., block material, block structure, block wall thickness, block heat dissipation performance, block stiffness, block dimensions, crankshaft bore, block machining process, block positioning reference) are obtained. Based on the target engine's operating conditions and the structural parameters of the target engine block, a finite element model of the target piston and piston cooling nozzles is established. The temperature field distribution of the target piston is determined based on the finite element model to identify the areas of the target piston that require cooling, and the temperature changes of various parts of the piston under operating conditions are displayed. The areas with the highest temperatures on the piston are identified; these areas are usually the load areas that require the most cooling. For example, the piston top, the annular groove area, and the area near the pin hole are usually the areas with the highest heat load. Then, based on the temperature field distribution, the first load area and the second load area of ​​the target piston are determined.

[0087] As a specific example, such as Figure 5 As shown in the flowchart, the piston cooling nozzle design method of the present invention may include the following steps:

[0088] S501, determine the first load zone and the second load zone for cooling the target piston.

[0089] S502, determine the first spray angle of the first cooling nozzle based on the position of the first load area, and determine the second spray angle of the second cooling nozzle based on the position of the second load area.

[0090] S503, determine the first rated flow rate of the first control valve and the second rated flow rate of the second control valve based on the highest operating temperature of the target piston.

[0091] S504, determine the first diameter of the first cooling nozzle based on the first rated flow rate and the average linear velocity of the target piston, and determine the second diameter of the second cooling nozzle based on the second rated flow rate and the average linear velocity of the target piston.

[0092] S505, determine the first opening pressure threshold of the first control valve and the second opening pressure threshold of the second control valve based on the oil pressure curve and oil temperature curve of the target engine block.

[0093] S506, determine the first preload and first spring stiffness of the first pressure spring in the first control valve according to the first opening pressure threshold, determine the second preload and second spring stiffness of the second pressure spring in the second control valve according to the second opening pressure threshold, and determine the third preload and third spring stiffness of the temperature control spring in the second control valve according to the second opening pressure threshold.

[0094] S507, the first design parameters of the first control valve and the first cooling nozzle are determined based on the first injection angle, the first orifice diameter, the first opening pressure threshold, the first preload force, and the first spring stiffness.

[0095] S508, the second design parameters of the second control valve and the second cooling nozzle are determined based on the second injection angle, the second orifice diameter, the second opening pressure threshold, the second preload, the second spring stiffness, the third preload, and the third spring stiffness.

[0096] S509, design the piston cooling nozzle according to the first design parameters and the second design parameters.

[0097] S510, determine whether the design scheme meets the design requirements. If yes, proceed to step S511; otherwise, return to step S501.

[0098] S511, completed the design of piston cooling nozzles.

[0099] Therefore, this invention comprehensively considers various boundary conditions such as piston temperature field, main oil passage pressure, engine oil temperature, and piston operating speed. Combining CAE simulation analysis methods, it sets parameters such as rated flow rate, opening pressure, nozzle angle, nozzle cross-sectional area, spring preload, and spring stiffness, and verifies the design accuracy through a series of experimental schemes. This piston cooling nozzle design method aims to meet the piston cooling requirements while precisely controlling the oil injection direction and quantity. It effectively reduces potential deviations from experience-based designs, improves design efficiency, and optimizes the design selection and development process of engine piston cooling nozzles.

[0100] In summary, the piston cooling nozzle design method according to embodiments of the present invention determines a first load zone and a second load zone for cooling the target piston, and determines a first injection angle of the first cooling nozzle based on the position of the first load zone, and a second injection angle of the second cooling nozzle based on the position of the second load zone; determines a first rated flow rate of the first control valve and a second rated flow rate of the second control valve based on the highest operating temperature of the target piston, determines a first orifice diameter of the first cooling nozzle based on the first rated flow rate and the average linear velocity of the target piston, and determines a second orifice diameter of the second cooling nozzle based on the second rated flow rate and the average linear velocity of the target piston; and determines a first opening pressure threshold of the first control valve and a second opening pressure threshold of the second control valve based on the oil pressure curve and oil temperature curve of the target engine block. The first preload and first spring stiffness of the first pressure spring in the first control valve are determined based on the first opening pressure threshold. The second preload and second spring stiffness of the second pressure spring in the second control valve are determined based on the second opening pressure threshold. The third preload and third spring stiffness of the temperature control spring in the second control valve are determined based on the second opening pressure threshold. The first design parameters of the first control valve and the first cooling nozzle are determined based on the first injection angle, the first orifice diameter, the first opening pressure threshold, the first preload, and the first spring stiffness. The second design parameters of the second control valve and the second cooling nozzle are determined based on the second injection angle, the second orifice diameter, the second opening pressure threshold, the second preload, the second spring stiffness, the third preload, and the third spring stiffness. The piston cooling nozzle is designed based on the first and second design parameters. Therefore, this method determines whether the piston cooling nozzle is working by combining the actual operating conditions of the whole machine, and precisely controls the direction and amount of oil injection when the piston cooling nozzle is working. At the same time, it minimizes the demand on the oil pump capacity from the cooling system level, reduces energy waste, thereby further improving fuel economy, further improving the thermal efficiency of the whole machine, effectively reducing the deviation that may be caused by experience-based design, and improving design efficiency.

[0101] It should be noted that the above description describes some embodiments of the present invention. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims may be performed in a different order than that shown in the above embodiments and still achieve the desired results. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0102] Furthermore, although the operations of the method of the present invention are described in a specific order in the accompanying drawings, this does not require or imply that these operations must be performed in that specific order, or that all of the operations shown must be performed to achieve the desired result. Rather, the steps depicted in the flowchart may be performed in a different order. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0103] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this invention should have the ordinary meaning understood by those skilled in the art. The terms "first," "second," and similar terms used in the embodiments of this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0104] While the spirit and principles of the invention have been described with reference to several specific embodiments, it should be understood that the invention is not limited to the disclosed specific embodiments, and the division of aspects does not imply that features in these aspects cannot be combined for benefit; such division is merely for ease of description. The invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the appended claims is to be interpreted in the broadest sense, thereby encompassing all such modifications and equivalent structures and functions.

Claims

1. A method for designing a piston cooling nozzle, characterized in that, The piston cooling nozzle includes: valve body (1); The first valve seat (7) is disposed on the valve body (1); The second valve seat (8) is disposed on the valve body (1); A first control valve (2) is disposed on a first valve seat (7). The inner cavity of the first control valve (2) is selectively connected to the inner cavity of the first valve seat (7). The inner cavity of the first valve seat (7) is connected to the oil passage of the target engine cylinder. The first control valve (2) is configured to perform opening or closing actions according to the oil pressure of the target engine cylinder. The second control valve (3) is disposed on the second valve seat (8), the inner cavity of the second control valve (3) is selectively connected to the inner cavity of the second valve seat (8), and the inner cavity of the second valve seat (8) is connected to the oil passage of the target engine cylinder; the second control valve (3) is configured to perform opening or closing actions according to the oil pressure and oil temperature of the target engine cylinder; The first cooling nozzle (5) is disposed on the first valve seat (7) and communicates with the inner cavity of the first valve seat (7). The first cooling nozzle (5) is used to cool the first load area of ​​the target piston. The second cooling nozzle (6) is disposed on the second valve seat (8) and communicates with the inner cavity of the second valve seat (8). The second cooling nozzle (6) is used to cool the second load area of ​​the target piston. The design method includes: A first load zone and a second load zone for cooling the target piston are determined, and a first spray angle of the first cooling nozzle is determined based on the position of the first load zone, and a second spray angle of the second cooling nozzle is determined based on the position of the second load zone. The first rated flow rate of the first control valve and the second rated flow rate of the second control valve are determined based on the highest operating temperature of the target piston. The first diameter of the first cooling nozzle is determined based on the first rated flow rate and the average linear velocity of the target piston. The second diameter of the second cooling nozzle is determined based on the second rated flow rate and the average linear velocity of the target piston. The first opening pressure threshold of the first control valve and the second opening pressure threshold of the second control valve are determined based on the oil pressure curve and oil temperature curve of the target engine cylinder block. The first preload and first spring stiffness of the first pressure spring in the first control valve are determined based on the first opening pressure threshold. The second preload and second spring stiffness of the second pressure spring in the second control valve are determined based on the second opening pressure threshold. The third preload and third spring stiffness of the temperature control spring in the second control valve are determined based on the second opening pressure threshold. The first design parameters of the first control valve and the first cooling nozzle are determined based on the first injection angle, the first orifice diameter, the first opening pressure threshold, the first preload, and the first spring stiffness. The second design parameters of the second control valve and the second cooling nozzle are determined based on the second injection angle, the second orifice diameter, the second opening pressure threshold, the second preload, the second spring stiffness, the third preload, and the third spring stiffness. The piston cooling nozzle is designed based on the first design parameters and the second design parameters.

2. The design method for the piston cooling nozzle according to claim 1, characterized in that, The determination of the first load zone and the second load zone for cooling the target piston includes: A finite element model of the target piston and the piston cooling nozzle is established based on the operating conditions of the target engine and the structural parameters of the target engine cylinder block. The temperature field distribution of the target piston is determined based on the finite element model. The first load zone and the second load zone of the target piston are determined based on the temperature field distribution.

3. A piston cooling nozzle, characterized in that, It is applied to the design method of the piston cooling nozzle as described in any one of claims 1-2, wherein the piston cooling nozzle comprises: Valve body (1); The first valve seat (7) is disposed on the valve body (1); The second valve seat (8) is disposed on the valve body (1); A first control valve (2) is disposed on a first valve seat (7). The inner cavity of the first control valve (2) is selectively connected to the inner cavity of the first valve seat (7). The inner cavity of the first valve seat (7) is connected to the oil passage of the target engine cylinder. The first control valve (2) is configured to perform opening or closing actions according to the oil pressure of the target engine cylinder. The second control valve (3) is disposed on the second valve seat (8), the inner cavity of the second control valve (3) is selectively connected to the inner cavity of the second valve seat (8), and the inner cavity of the second valve seat (8) is connected to the oil passage of the target engine cylinder; the second control valve (3) is configured to perform opening or closing actions according to the oil pressure and oil temperature of the target engine cylinder; The first cooling nozzle (5) is disposed on the first valve seat (7) and communicates with the inner cavity of the first valve seat (7). The first cooling nozzle (5) is used to cool the first load area of ​​the target piston. The second cooling nozzle (6) is disposed on the second valve seat (8) and communicates with the inner cavity of the second valve seat (8). The second cooling nozzle (6) is used to cool the second load zone of the target piston.

4. The piston cooling nozzle according to claim 3, characterized in that, The valve body (1) is provided with a first limiting hole, and the first valve seat (7) passes through the first limiting hole and is fixedly disposed on the valve body (1).

5. The piston cooling nozzle according to claim 3, characterized in that, The valve body (1) is provided with a second limiting hole, and the second valve seat (8) passes through the second limiting hole and is fixedly installed on the valve body (1).

6. The piston cooling nozzle according to claim 4, characterized in that, The inner contour of the first valve seat (7) is provided with an internal thread structure, and the outer contour of the first control valve (2) is provided with an external thread structure. The first control valve (2) passes through the first valve seat (7) and is fixed on the first valve seat (7) by the external thread structure in conjunction with the internal thread structure of the first valve seat (7). The first control valve (2) is in conjunction with the first preset through hole of the target engine cylinder by the internal thread structure, so that the inner cavity of the first control valve (2) is connected to the oil passage of the target engine cylinder by the first preset through hole.

7. The piston cooling nozzle according to claim 5, characterized in that, The bottom of the second control valve (3) engages with the second preset through hole of the target engine cylinder, so that the inner cavity of the second control valve (3) is connected to the oil passage of the target engine cylinder through the second preset through hole.

8. The piston cooling nozzle according to claim 7, characterized in that, A sealing ring (4) is provided at the connection between the second valve seat (8) and the oil passage of the target engine cylinder.

9. The piston cooling nozzle according to claim 6, characterized in that, The first control valve (2) includes a first sealing cover (21), a first pressure spring (22), and a first plunger (23); One end of the first pressure spring (22) is connected to the first sealing cover plate (21), and the other end of the first pressure spring (22) is connected to the first plunger (23); The first plunger (23) is used to generate force on the first pressure spring (22) under the action of the oil pressure of the target engine cylinder, so as to compress the first pressure spring (22) and drive the first plunger (23) to move in the compression direction of the first pressure spring (22) to control the communication state between the inner cavity of the first control valve (2) and the oil passage of the target engine cylinder.

10. The piston cooling nozzle according to claim 7, characterized in that, The second control valve (3) includes a second sealing cover (31), a thermo-pressure spring assembly, and a second plunger (33); the thermo-pressure spring assembly includes a second pressure spring (34) and a temperature control spring (35); One end of the thermo-pressure spring assembly is connected to the second sealing cover plate (31), and the other end of the thermo-pressure spring assembly is connected to the second plunger (33); The second plunger (33) is used to exert force on the second pressure spring (34) under the action of the oil pressure of the target engine cylinder, so as to compress the second pressure spring (34) and drive the second plunger (33) to move in the compression direction of the second pressure spring (34) to control the communication state between the inner cavity of the second control valve (3) and the oil passage of the target engine cylinder; or / and, the temperature control spring (35) is used to generate compression under the action of the oil temperature of the target engine cylinder, so as to drive the second plunger (33) to move in the compression direction of the temperature control spring (35) to control the communication state between the inner cavity of the second control valve (3) and the oil passage of the target engine cylinder.

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