A high-efficiency atomizing injection system for direct injection injectors

Abstract

The present invention relates to the field of fuel injector technology, and in particular to an efficient atomizing injection system for a direct injection fuel injector in a cylinder. The technical solution includes: the injection execution unit adopts an asymmetric spray hole array by laser cladding, and utilizes the aperture gradient distribution and logarithmic spiral arrangement to evenly distribute the fuel in the combustion chamber and enhance the oil-gas mixing effect. The dynamic pressure regulation unit integrates a MEMS thin film sensor array and a fuzzy neural network controller. The sensor can accurately monitor the fuel pressure in real time. The controller is based on a 7-12-3 type BP network. After a large amount of data training, it can quickly and accurately adjust the injection pressure according to the engine working conditions. The fuel pretreatment unit includes an ultrasonic cavitation device and a graded heating system. The former reduces the viscosity of the fuel, and the latter uses a PTC heater, a semiconductor laser and a vortex generator to accurately control the temperature. The three major units work together to greatly improve the fuel atomization and combustion efficiency, reduce pollutant emissions, and significantly improve engine performance.

Description

Technical Field

[0001] The invention relates to the technical field of fuel injection nozzles, and in particular to a high-efficiency atomizing injection system for an in-cylinder direct injection fuel injector. Background Art

[0002] The fuel injector is a normally closed valve. When the electromagnetic coil is energized, suction is generated, the needle valve is sucked up, the spray hole is opened, and the fuel is sprayed out at high speed through the annular gap between the needle at the head of the needle valve and the spray hole, forming a mist, which is conducive to complete combustion.

[0003] After searching, the patent application number CN202420980718.0 discloses a fuel injection nozzle for Delphi DFI2.5 fuel injector. Although the device realizes fuel injection in different directions by setting the first injection assembly and the second injection assembly when in use, it helps to increase the contact area between fuel and air. However, when the device is in use, it is impossible to accurately adjust the differentiated requirements of fuel quantity and injection speed in different areas of the combustion chamber, resulting in poor uniformity of the mixed gas, difficulty in further improving the combustion efficiency, and relatively high pollutant emissions. At the same time, the flow state of the fuel in the pore is single, and it is impossible to form an effective internal disturbance, resulting in unsatisfactory fuel atomization effect, affecting the full degree of combustion. In terms of pressure regulation, it is impossible to quickly and accurately sense the change of fuel pressure, and it is difficult to achieve real-time and accurate regulation of the injection pressure, which greatly reduces the performance stability of the engine under complex working conditions. In addition, the device cannot effectively improve the physical properties of the fuel, and cannot ensure that the fuel is injected under the optimal temperature and viscosity conditions, which reduces the working efficiency of the entire fuel injection system and the overall performance of the engine. Summary of the invention

[0004] In view of the deficiencies of the prior art, the present invention provides a high-efficiency atomizing injection system for an in-cylinder direct injection injector, which solves the problems raised in the background technology.

[0005] The solution of the present invention to solve the above technical problems is as follows:

[0006] A high-efficiency atomizing injection system for a direct-injection fuel injector in a cylinder, comprising:

[0007] a) The injection execution unit is composed of an asymmetric nozzle array formed by laser cladding, and the nozzle array satisfies the logarithmic spiral arrangement relationship:

[0008] r: radial distance from the nozzle center to the spiral origin, unit: mm;

[0009] θ: polar angle corresponding to the nozzle position, unit: radian;

[0010] a: initial radius coefficient of the helix, related to the diameter of the combustion chamber;

[0011] b: Spiral growth rate coefficient, the core parameter controlling the distribution density of nozzle holes;

[0012] The value range of parameter a is 0.23 mm ≤ a ≤ 0.27 mm, the value range of parameter b is 0.12 ≤ b ≤ 0.18, and the axis of the nozzle and the tangent of the combustion chamber form an angle of 15° to 19°;

[0013] b) A dynamic pressure regulation unit, integrating a MEMS thin film sensor array and a fuzzy neural network controller, the controller executing a fourth-order pressure control algorithm:

[0014]

[0015] ΔP: injection pressure adjustment, unit: MPa;

[0016] e(t): real-time pressure error, , unit: MPa;

[0017] Kp, Ki, Kd: proportional, integral and differential coefficients of PID control;

[0018] α: working condition self-learning coefficient, dynamically adjust the algorithm weight;

[0019] Among them, the value range of the working condition self-learning coefficient is 0.2≤α≤0.8, and it is dynamically adjusted through the fuzzy rule base;

[0020] c) A fuel pretreatment unit, including an ultrasonic cavitation device and a staged heating system, wherein the ultrasonic cavitation device has an operating frequency of 25kHz to 30kHz, a power density of 12W / cm2 to 18W / cm2, and a cavitation number σ satisfies:

[0021]

[0022] Where P υ is the saturated vapor pressure of fuel, P is the local static pressure, ρ is the fuel density, and V is the characteristic flow velocity;

[0023] The injection execution unit is connected to the outlet of the fuel pretreatment unit through a conical transition cavity, the conical transition cavity has a cone angle of 12°±0.5° and a length-to-diameter ratio of 3:1, and the dynamic pressure adjustment unit is electrically connected to the sensor array through a coaxial shielded signal line, and the shielding effectiveness of the coaxial shielded signal line is ≥60dB.

[0024] Based on the above technical solution, the present invention can also be improved as follows.

[0025] Furthermore, the apertures of the nozzle array are distributed in a gradient manner, satisfying:

[0026]

[0027] Wherein Δd is the diameter difference of adjacent nozzles, N is the nozzle number counted from the center to the edge, the nozzle diameter in the center area is 0.10 mm to 0.14 mm, and the nozzle diameter in the edge area is 0.16 mm to 0.2 mm.

[0028] The beneficial effects of adopting the above further scheme are:

[0029] The aperture of the nozzle array is distributed in a gradient, which enables the fuel to be sprayed at different flow rates and speeds from the center to the edge during the injection process. The nozzle diameter in the center area is smaller, the amount of fuel sprayed is relatively small, and the speed is higher, which is conducive to forming a denser combustible mixture in the center of the combustion chamber; the nozzle diameter in the edge area is larger, the amount of fuel sprayed is larger, and the speed is relatively low, which can make the fuel better cover the edge area of ​​the combustion chamber and improve the uniformity of the mixture. This distribution method, combined with the logarithmic spiral arrangement and the tangential angle between the nozzle and the combustion chamber, can optimize the fuel injection trajectory, enhance the mixing effect of fuel and air, and thus improve combustion efficiency and reduce pollutant emissions.

[0030] Furthermore, the inner wall of the injection nozzle channel of the injection execution unit is provided with a periodic micro-groove structure, the groove depth is 18μm~22μm, the spacing is 48μm~52μm, the groove cross-section is an asymmetric trapezoid, the leading edge inclination angle is 55°~65°, the trailing edge inclination angle is 30°~40°, and the surface Vickers hardness is ≥800 HV.

[0031] The beneficial effects of adopting the above further scheme are:

[0032] The periodic micro-groove structure on the inner wall of the nozzle channel can increase the contact area between the fuel and the inner wall when the fuel passes through the channel, making the interaction more complex. The special structural design of the micro-groove, such as the asymmetric trapezoidal cross-section and the specific leading and trailing edge inclination angles, will change the flow state of the fuel, promote the formation of turbulence in the channel, and enhance the internal disturbance of the fuel. This disturbance helps to further break up the fuel before injection, thereby improving the atomization quality of the fuel after injection, allowing the fuel to be more fully mixed with the air, improving the combustion effect, and improving the power performance and fuel economy of the engine.

[0033] Furthermore, the MEMS thin film sensor array of the dynamic pressure regulating unit includes three groups of piezoresistive sensors with a measuring range of 0MPa to 50MPa, a response time of ≤0.25ms, a nonlinear error of ≤0.05%FS, and a temperature drift coefficient of ≤0.002%FS / °C.

[0034] The beneficial effects of adopting the above further scheme are:

[0035] The MEMS thin film sensor array of the dynamic pressure regulation unit has a wide range (0 MPa-50 MPa), which can meet the fuel pressure measurement requirements of the engine under different working conditions. The extremely short response time (≤0.25 ms) can quickly sense the changes in fuel pressure and realize real-time monitoring of pressure. The extremely small nonlinear error (≤0.05% FS) and temperature drift coefficient (≤0.002% FS / ℃) ensure the high accuracy and stability of the measurement data without excessive interference from environmental factors such as temperature. These characteristics provide the fuzzy neural network controller with accurate and reliable pressure data, enabling it to accurately calculate and adjust the injection pressure according to actual conditions, ensuring stable and efficient operation of the fuel injection system.

[0036] Furthermore, the fuzzy neural network controller adopts a 7-12-3 BP network topology structure, the input layer includes seven parameters including speed, load, intake temperature, oxygen concentration, injection pressure, injection pulse width and fuel viscosity, the training data set includes ≥105 groups of transient operating condition data, the network convergence condition is mean square error MSE≤0.005, and the learning rate adaptive adjustment range is 0.01 to 0.1.

[0037] The beneficial effects of adopting the above further scheme are:

[0038] The fuzzy neural network controller adopts a 7-12-3 BP network topology. The input layer contains multiple parameters closely related to the engine operating conditions (speed, load, intake temperature, oxygen concentration, injection pressure, injection pulse width and fuel viscosity), which can fully obtain the real-time operating status information of the engine. With a training data set of ≥105 sets of transient operating condition data, the controller has a rich learning sample and can better adapt to various complex working conditions. Strict network convergence conditions (mean square error MSE≤0.005) and a learning rate with an adaptive adjustment range of 0.01-0.1 ensure the accuracy and stability of the controller during the learning process. Through these designs, the controller can quickly and accurately calculate the injection pressure adjustment amount according to different working conditions, dynamically adjust the injection pressure, so that the fuel injection is always in the best state, effectively improve the combustion performance and stability of the engine, and reduce fuel consumption and emissions.

[0039] Further, the hierarchical heating system comprises:

[0040] First-stage preheating module: PTC heater is used to heat the fuel to 38℃~42℃, with thermal efficiency ≥93%;

[0041] Secondary precision temperature control module: uses a semiconductor laser with a wavelength of 980mm to raise the temperature of the fuel to 78℃~82℃, with a temperature control accuracy of ±0.5℃, and a vortex generator is set between the two-stage modules, with a height of 1 / 5~1 / 3 of the flow channel diameter.

[0042] The beneficial effects of adopting the above further scheme are:

[0043] The first-stage preheating module of the graded heating system uses a PTC heater to heat the fuel to 38℃-42℃. It has the advantage of high thermal efficiency (≥93%), and can quickly and efficiently preheat the fuel, increase the temperature of the fuel, and reduce the viscosity of the fuel, preparing for subsequent precise heating. The second-stage precision temperature control module uses a semiconductor laser with a wavelength of 980 mm to heat the fuel to 78℃-82℃. The temperature control accuracy can reach ±0.5℃, realizing precise control of the fuel temperature and ensuring that the fuel reaches the optimal injection temperature. The vortex generator set between the two-stage modules has a height of 1 / 5-1 / 3 of the flow channel diameter, which can change the flow state of the fuel, generate vortices, enhance the mixing and heat exchange inside the fuel, further improve the preheating effect of the fuel, ensure uniform and stable fuel temperature, optimize the atomization and mixing performance of the fuel, and improve the combustion efficiency and performance of the engine.

[0044] Furthermore, the inner wall of the conical transition cavity is coated with a nanocomposite coating, and the coating composition is:

[0045] Base material: C r3 C2-NiCr, mass ratio 7:3;

[0046] Nano additives: Al2O3-TiO2 core-shell structure particles, particle size 80nm~120nm, addition amount 8%~12%;

[0047] The coating thickness is 50μm to 80μm, the porosity is ≤0.5%, and the friction coefficient is ≤0.18.

[0048] The beneficial effects of adopting the above further scheme are:

[0049] Nanocomposite coating on the inner wall of the tapered transition cavity, with C r3 C2-NiCr is the base material (mass ratio 7:3), with Al2O3-TiO2 core-shell structure nanoparticles (particle size 80 nm-120 nm, addition amount 8%-12%) added, which has the characteristics of moderate thickness (50μm-80μm), low porosity (≤0.5%), and low friction coefficient (≤0.18). Low porosity reduces the risk of fuel penetration and leakage, and low friction coefficient can effectively reduce the energy loss and flow resistance of fuel when flowing in the transition cavity, ensuring that the pre-treated fuel can smoothly and efficiently enter the injection execution unit, ensuring the working stability and reliability of the fuel injection system.

[0050] Furthermore, the fuel modification effect of the ultrasonic cavitation device satisfies:

[0051] Where η is the fuel dynamic viscosity, T is the fuel temperature, A, B, C are the fuel physical constants calibrated by experiments, for example, diesel: A=−3.2, B=1200, C=150, after pretreatment, T rises from −30℃ to 80℃, η rises from 12.5mm 2 / s down to 4.3mm 2 / s, and the atomization angle is maintained at 85°±2°.

[0052] The beneficial effects of adopting the above further scheme are:

[0053] The fuel modification effect of the ultrasonic cavitation device meets a specific formula. For diesel and other fuels, the temperature rises from -30°C to 80°C after pretreatment, the dynamic viscosity drops from 12.5 mm² / s to 4.3 mm² / s, and the atomization angle is maintained at 85°±2°. The reduction in fuel viscosity significantly improves the fluidity of the fuel, making the fuel smoother in the subsequent injection and atomization process, which is conducive to the formation of finer oil droplets and improves the atomization quality. The increase in temperature helps the volatilization and mixing of the fuel, and the stability of the atomization angle ensures that the distribution range and shape of the fuel in the combustion chamber are relatively stable, thereby optimizing the mixing effect of fuel and air, improving combustion efficiency, enhancing the power output of the engine, and reducing pollutant emissions.

[0054] Furthermore, the fuel injector is manufactured by a selective laser melting process, with a laser power of 280 W ± 5%, a scanning speed of 800 mm / s ± 5%, a layer thickness of 30 μm, and a vacuum heat treatment at 1050° C. × 2 h after forming, with a residual stress of ≤50 MPa.

[0055] The beneficial effects of adopting the above further scheme are:

[0056] The fuel injector is manufactured by the selective laser melting process. During the manufacturing process, the laser power (280 W ± 5%), scanning speed (800 mm / s ± 5%) and layer thickness (30 μm) are precisely controlled to ensure high-precision manufacturing of the fuel injector and ensure that the dimensional accuracy and shape accuracy of the nozzle meet the design requirements. After forming, the residual stress is reduced to ≤ 50 MPa by vacuum heat treatment at 1050℃ × 2 h, which effectively eliminates the residual stress generated during the manufacturing process and improves the structural strength and stability of the fuel injector. This enables the fuel injector to maintain good performance in a long-term high-pressure fuel injection working environment, reduces the risk of deformation and damage, improves the reliability and service life of the fuel injector, and ensures the stable operation of the fuel injection system.

[0057] Furthermore, the dynamic response time of the system composed of the injection execution unit, the dynamic pressure regulation unit and the fuel pretreatment unit is ≤35ms, the pressure fluctuation rate is ≤3.8%, and the Sauter mean diameter under a −30°C environment is 18.7μm±0.5μm, and the standard deviation of the particle size distribution is ≤4.2μm.

[0058] The beneficial effects of adopting the above further scheme are:

[0059] The system composed of the injection execution unit, dynamic pressure regulation unit and fuel pretreatment unit has a dynamic response time of ≤35 ms, which means that the system can quickly respond to changes in engine operating conditions, adjust fuel injection and pressure control in time, and ensure that the engine can quickly enter a stable operating state under different operating conditions. The pressure fluctuation rate is ≤3.8%, which ensures the stability of the fuel injection pressure and avoids excessive pressure fluctuations that affect the fuel atomization effect and combustion performance. The average diameter of the Sauter at -30℃ is 18.7μm±0.5μm, and the standard deviation of the particle size distribution is ≤4.2μm, indicating that the system can still maintain good fuel atomization performance in a low temperature environment, so that the fuel can be evenly and fully mixed with the air to achieve efficient combustion. These performance indicators ensure that the system can work stably and efficiently under different environmental conditions, effectively improve the combustion efficiency and performance of the engine, reduce pollutant emissions, and improve the overall reliability and adaptability of the engine.

[0060] The present invention provides a high-efficiency atomizing injection system for a direct-injection fuel injector in a cylinder, which has the following beneficial effects:

[0061] The nozzle array adopts an asymmetric design and the aperture is distributed in a gradient. The diameter difference of adjacent nozzles has a specific pattern. This design can form different injection angles and speeds when the fuel is injected, which helps to distribute the fuel more evenly in the combustion chamber and improve combustion efficiency. The nozzles are arranged in a logarithmic spiral line. By reasonably setting the initial radius coefficient of the spiral line and the spiral growth rate coefficient, the distribution density of the nozzles can be accurately controlled, so that the fuel injection coverage is more reasonable, better matching the combustion chamber shape and airflow movement, and reducing undesirable phenomena such as fuel hitting the wall. The angle formed by the nozzle axis and the tangent of the combustion chamber can make the fuel injection direction and the airflow movement direction in the combustion chamber cooperate with each other, enhance the mixing effect of fuel and air, and help form a more ideal combustible mixture.

[0062] The inner wall of the nozzle channel is provided with a periodic micro-groove structure, and the groove cross section is an asymmetric trapezoid. This structure can make the interaction between the fuel and the inner wall of the channel more complex during the fuel injection process, promote the fragmentation and atomization of the fuel, and improve the atomization quality. The nozzle is manufactured by the selective laser melting process and vacuum heat treatment, which can ensure the accuracy and performance of the nozzle, reduce residual stress, and improve the reliability and service life of the nozzle.

[0063] The fuzzy neural network controller is integrated and executes the fourth-order pressure control algorithm. Through the real-time pressure error and the proportional, integral, differential coefficients and working condition self-learning coefficients of PID control, the injection pressure can be accurately adjusted according to different working conditions, so that the fuel injection pressure is always kept in the best state, ensuring the fuel atomization effect and combustion performance. The working condition self-learning coefficient can be taken within a certain range and dynamically adjusted through the fuzzy rule base, so that the system can better adapt to various complex working conditions and improve the flexibility and adaptability of pressure control.

[0064] The MEMS thin film sensor array contains three groups of piezoresistive sensors, which have the advantages of suitable range, short response time, small nonlinear error and low temperature drift coefficient. It can accurately and quickly measure parameters such as fuel pressure and provide precise data support for pressure regulation.

[0065] The fuzzy neural network controller adopts a 7-12-3 BP network topology. The input layer contains multiple parameters related to the engine operating conditions. The training data set is rich, the network convergence conditions are strict, and the learning rate can be adaptively adjusted, so that the controller can accurately and efficiently control the pressure regulation under various operating conditions and improve the overall performance of the system.

[0066] Ultrasonic cavitation device produces cavitation effect on fuel through specific working frequency and power density. The cavitation number and fuel modification effect have specific calculation formulas and good results. For fuels such as diesel, it can effectively reduce fuel dynamic viscosity, improve fuel fluidity and atomization performance, and maintain a suitable atomization angle, which is conducive to the full mixing of fuel and air.

[0067] The hierarchical heating system uses a PTC heater and a semiconductor laser with a specific wavelength as the first-level preheating module and the second-level precise temperature control module, respectively, which can gradually increase the fuel temperature from a low temperature to a suitable temperature with high temperature control accuracy. Vortex generators are set between different modules to enhance the disturbance of the fuel in the flow channel and further improve the mixing and preheating effect of the fuel.

[0068] The injection execution unit is connected to the outlet of the fuel pretreatment unit through a conical transition chamber. The cone angle and aspect ratio of the conical transition chamber are reasonably designed. The nano-composite coating coated on the inner wall has a specific composition and good properties, such as low porosity and small friction coefficient, which helps to reduce the energy loss and flow resistance of the fuel during the transition process, ensure that the fuel enters the injection execution unit smoothly, and improve the overall efficiency of the system.

[0069] The system has a short dynamic response time, a small pressure fluctuation rate, and good Sauter mean diameter and particle size distribution standard deviation under low temperature conditions, indicating that the entire system can work quickly and stably, and can ensure efficient atomization and injection of fuel under different environmental conditions, improve the combustion efficiency and performance of the engine, reduce pollutant emissions, and has high reliability and practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] The drawings described herein are used to provide further understanding of the present invention and constitute a part of this application. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0071] In the attached picture:

[0072] Figure 1 It is a schematic diagram of the workflow of the present invention;

[0073] Figure 2 This is a schematic diagram of the fuel pretreatment process of the present invention;

[0074] Figure 3 It is a schematic diagram of the flow chart of the injection execution phase of the present invention;

[0075] Figure 4 It is a schematic diagram of the process flow of the pressure dynamic regulation stage of the present invention. DETAILED DESCRIPTION

[0076] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0077] See also Figures 1 to 4 As shown, the embodiments provided by the present invention are:

[0078] Embodiment 1: The injection execution unit is composed of an asymmetric nozzle array formed by laser cladding, and the aperture of the nozzle array is distributed in a gradient manner, satisfying:

[0079]

[0080] Where Δd is the diameter difference between adjacent nozzles, N is the nozzle number counted from the center to the edge, the nozzle diameter in the center area is 0.10mm-0.14mm, and the nozzle diameter in the edge area is 0.16mm-0.2mm;

[0081] The aperture of the nozzle array is distributed in a gradient, which enables the fuel to be sprayed at different flow rates and speeds from the center to the edge during the injection process. The nozzle diameter in the center area is smaller, the amount of fuel sprayed is relatively small, and the speed is higher, which is conducive to forming a denser combustible mixture in the center of the combustion chamber; the nozzle diameter in the edge area is larger, the amount of fuel sprayed is larger, and the speed is relatively low, which can make the fuel better cover the edge area of ​​the combustion chamber and improve the uniformity of the mixture. This distribution method, combined with the logarithmic spiral arrangement and the tangential angle between the nozzle and the combustion chamber, can optimize the fuel injection trajectory, enhance the mixing effect of fuel and air, and thus improve combustion efficiency and reduce pollutant emissions.

[0082] The nozzle array satisfies the logarithmic spiral arrangement relationship:

[0083] r: radial distance from the nozzle center to the spiral origin, unit: mm;

[0084] θ: polar angle corresponding to the nozzle position, unit: radian;

[0085] a: initial radius coefficient of the helix, related to the diameter of the combustion chamber;

[0086] b: Spiral growth rate coefficient, the core parameter controlling the distribution density of nozzle holes;

[0087] The value range of parameter a is 0.23 mm ≤ a ≤ 0.27 mm, the value range of parameter b is 0.12 ≤ b ≤ 0.18, and the axis of the nozzle and the tangent of the combustion chamber form an angle of 15° to 19°;

[0088] The inner wall of the nozzle channel of the injection execution unit is provided with a periodic micro-groove structure, with a groove depth of 18μm to 22μm, a spacing of 48μm to 52μm, an asymmetric trapezoidal groove section, a leading edge inclination of 55° to 65°, a trailing edge inclination of 30° to 40°, and a surface Vickers hardness of ≥800 HV; the periodic micro-groove structure on the inner wall of the nozzle channel can increase the contact area between the fuel and the inner wall when passing through the channel, and the interaction is more complex. The special structural design of the micro-groove, such as the asymmetric trapezoidal cross-section and the specific leading and trailing edge inclinations, will change the flow state of the fuel, promote the formation of turbulence in the channel, and enhance the internal disturbance of the fuel. This disturbance helps the fuel to be further broken before injection, thereby improving the atomization quality of the fuel after injection, so that the fuel can be more fully mixed with the air, improve the combustion effect, and improve the power performance and fuel economy of the engine. The fuel injector nozzle is manufactured by selective laser melting process, with laser power of 280W±5%, scanning speed of 800mm / s±5%, layer thickness of 30μm, and vacuum heat treatment at 1050℃×2h after forming, and residual stress ≤50MPa.

[0089] The fuel injector is manufactured by the selective laser melting process. During the manufacturing process, the laser power (280 W ± 5%), scanning speed (800 mm / s ± 5%) and layer thickness (30 μm) are precisely controlled to ensure high-precision manufacturing of the fuel injector and ensure that the dimensional accuracy and shape accuracy of the nozzle meet the design requirements. After forming, the residual stress is reduced to ≤ 50 MPa by vacuum heat treatment at 1050℃ × 2 h, which effectively eliminates the residual stress generated during the manufacturing process and improves the structural strength and stability of the fuel injector. This enables the fuel injector to maintain good performance in a long-term high-pressure fuel injection working environment, reduces the risk of deformation and damage, improves the reliability and service life of the fuel injector, and ensures the stable operation of the fuel injection system.

[0090] Example 2: In order to dynamically adjust the pressure, for example, Figures 1 to 4 As shown, the present invention also includes:

[0091] Dynamic pressure regulation unit, integrating MEMS thin film sensor array and fuzzy neural network controller, the controller executes the fourth-order pressure control algorithm:

[0092]

[0093] ΔP: injection pressure adjustment, unit: MPa;

[0094] e(t): real-time pressure error, , unit: MPa;

[0095] Kp, Ki, Kd: proportional, integral and differential coefficients of PID control;

[0096] α: working condition self-learning coefficient, dynamically adjust the algorithm weight;

[0097] Among them, the value range of the working condition self-learning coefficient is 0.2≤α≤0.8, and it is dynamically adjusted through the fuzzy rule base;

[0098] The MEMS thin film sensor array of the dynamic pressure regulation unit includes three groups of piezoresistive sensors with a measuring range of 0MPa to 50MPa, a response time of ≤0.25ms, a nonlinear error of ≤0.05%FS, and a temperature drift coefficient of ≤0.002%FS / ℃.

[0099] The MEMS thin film sensor array of the dynamic pressure regulation unit has a wide range (0 MPa-50 MPa), which can meet the fuel pressure measurement requirements of the engine under different working conditions. The extremely short response time (≤0.25 ms) can quickly sense the changes in fuel pressure and realize real-time monitoring of pressure. The extremely small nonlinear error (≤0.05% FS) and temperature drift coefficient (≤0.002% FS / ℃) ensure the high accuracy and stability of the measurement data without excessive interference from environmental factors such as temperature. These characteristics provide the fuzzy neural network controller with accurate and reliable pressure data, enabling it to accurately calculate and adjust the injection pressure according to actual conditions, ensuring stable and efficient operation of the fuel injection system.

[0100] The fuzzy neural network controller adopts a 7-12-3 BP network topology. The input layer contains seven parameters: speed, load, intake temperature, oxygen concentration, injection pressure, injection pulse width and fuel viscosity. The training data set contains ≥105 sets of transient operating condition data. The network convergence condition is mean square error MSE≤0.005, and the learning rate adaptive adjustment range is 0.01~0.1.

[0101] The fuzzy neural network controller adopts a 7-12-3 BP network topology. The input layer contains multiple parameters closely related to the engine operating conditions (speed, load, intake temperature, oxygen concentration, injection pressure, injection pulse width and fuel viscosity), which can fully obtain the real-time operating status information of the engine. With a training data set of ≥105 sets of transient operating condition data, the controller has a rich learning sample and can better adapt to various complex working conditions. Strict network convergence conditions (mean square error MSE≤0.005) and a learning rate with an adaptive adjustment range of 0.01-0.1 ensure the accuracy and stability of the controller during the learning process. Through these designs, the controller can quickly and accurately calculate the injection pressure adjustment amount according to different working conditions, dynamically adjust the injection pressure, so that the fuel injection is always in the best state, effectively improve the combustion performance and stability of the engine, and reduce fuel consumption and emissions.

[0102] Embodiment 3: In order to pre-treat the fuel, for example, Figures 1 to 4 As shown, the present invention also includes: a fuel pretreatment unit, including an ultrasonic cavitation device and a staged heating system, wherein the ultrasonic cavitation device has an operating frequency of 25kHz to 30kHz, a power density of 12W / cm2 to 18W / cm2, and a cavitation number σ satisfies:

[0103]

[0104] Where P υ is the saturated vapor pressure of fuel, P is the local static pressure, ρ is the fuel density, and V is the characteristic flow velocity;

[0105] The fuel modification effect of ultrasonic cavitation device meets the following requirements:

[0106]

[0107] Where η is the fuel dynamic viscosity, T is the fuel temperature, A, B, C are the fuel physical constants calibrated by experiments, for example, diesel: A=−3.2, B=1200, C=150, after pretreatment, T rises from −30℃ to 80℃, η rises from 12.5mm 2 / s down to 4.3mm 2 / s, and the atomization angle is maintained at 85°±2°.

[0108] The fuel modification effect of the ultrasonic cavitation device meets a specific formula. For diesel and other fuels, the temperature rises from -30°C to 80°C after pretreatment, the dynamic viscosity drops from 12.5 mm² / s to 4.3 mm² / s, and the atomization angle is maintained at 85°±2°. The reduction in fuel viscosity significantly improves the fluidity of the fuel, making the fuel smoother in the subsequent injection and atomization process, which is conducive to the formation of finer oil droplets and improves the atomization quality. The increase in temperature helps the volatilization and mixing of the fuel, and the stability of the atomization angle ensures that the distribution range and shape of the fuel in the combustion chamber are relatively stable, thereby optimizing the mixing effect of fuel and air, improving combustion efficiency, enhancing the power output of the engine, and reducing pollutant emissions.

[0109] The staged heating system includes:

[0110] First-stage preheating module: PTC heater is used to heat the fuel to 38℃~42℃, with thermal efficiency ≥93%;

[0111] Secondary precision temperature control module: uses a semiconductor laser with a wavelength of 980mm to raise the temperature of the fuel to 78℃~82℃, with a temperature control accuracy of ±0.5℃, and a vortex generator is set between the two-stage modules, with a height of 1 / 5~1 / 3 of the flow channel diameter.

[0112] The first-stage preheating module of the graded heating system uses a PTC heater to heat the fuel to 38℃-42℃. It has the advantage of high thermal efficiency (≥93%), and can quickly and efficiently preheat the fuel, increase the temperature of the fuel, and reduce the viscosity of the fuel, preparing for subsequent precise heating. The second-stage precision temperature control module uses a semiconductor laser with a wavelength of 980 mm to heat the fuel to 78℃-82℃. The temperature control accuracy can reach ±0.5℃, realizing precise control of the fuel temperature and ensuring that the fuel reaches the optimal injection temperature. The vortex generator set between the two-stage modules has a height of 1 / 5-1 / 3 of the flow channel diameter, which can change the flow state of the fuel, generate vortices, enhance the mixing and heat exchange inside the fuel, further improve the preheating effect of the fuel, ensure uniform and stable fuel temperature, optimize the atomization and mixing performance of the fuel, and improve the combustion efficiency and performance of the engine.

[0113] The injection execution unit is connected to the outlet of the fuel pretreatment unit through a conical transition cavity. The conical transition cavity has a cone angle of 12°±0.5° and an aspect ratio of 3:1. The inner wall of the conical transition cavity is coated with a nanocomposite coating, and the coating composition is:

[0114] Base material: C r3 C2-NiCr, mass ratio 7:3;

[0115] Nano additives: Al2O3-TiO2 core-shell structure particles, particle size 80nm~120nm, addition amount 8%~12%;

[0116] The coating thickness is 50μm to 80μm, the porosity is ≤0.5%, and the friction coefficient is ≤0.18;

[0117] Nanocomposite coating on the inner wall of the tapered transition cavity, with C r3 C2-NiCr is the base material (mass ratio 7:3), with Al2O3-TiO2 core-shell structure nanoparticles (particle size 80nm-120nm, addition amount 8%-12%) added, with moderate thickness (50μm-80μm), low porosity (≤0.5%), and low friction coefficient (≤0.18). Low porosity reduces the risk of fuel penetration and leakage, and low friction coefficient can effectively reduce the energy loss and flow resistance of fuel when flowing in the transition cavity, ensuring that the pre-treated fuel can smoothly and efficiently enter the injection execution unit, ensuring the working stability and reliability of the fuel injection system.

[0118] The dynamic pressure regulating unit is electrically connected to the sensor array through a coaxial shielded signal line, and the shielding effectiveness of the coaxial shielded signal line is ≥60dB.

[0119] The dynamic response time of the system composed of the injection execution unit, dynamic pressure regulation unit and fuel pretreatment unit is ≤35ms, the pressure fluctuation rate is ≤3.8%, and the Sauter mean diameter under −30℃ environment is 18.7μm±0.5μm, and the standard deviation of particle size distribution is ≤4.2μm.

[0120] The system composed of the injection execution unit, dynamic pressure regulation unit and fuel pretreatment unit has a dynamic response time of ≤35 ms, which means that the system can quickly respond to changes in engine operating conditions, adjust fuel injection and pressure control in time, and ensure that the engine can quickly enter a stable operating state under different operating conditions. The pressure fluctuation rate is ≤3.8%, which ensures the stability of the fuel injection pressure and avoids excessive pressure fluctuations that affect the fuel atomization effect and combustion performance. The average diameter of the Sauter at -30℃ is 18.7μm±0.5μm, and the standard deviation of the particle size distribution is ≤4.2μm, indicating that the system can still maintain good fuel atomization performance in a low temperature environment, so that the fuel can be evenly and fully mixed with the air to achieve efficient combustion. These performance indicators ensure that the system can work stably and efficiently under different environmental conditions, effectively improve the combustion efficiency and performance of the engine, reduce pollutant emissions, and improve the overall reliability and adaptability of the engine.

[0121] Working principle:

[0122] Fuel pretreatment stage

[0123] Ultrasonic cavitation treatment: The fuel first enters the ultrasonic cavitation device, which operates at a specific frequency (25kHz~30kHz) and power density (12W / cm 2 ~18W / cm 2 ) operation. The working principle is based on the cavitation effect generated when ultrasound propagates in liquid. The cavitation number must satisfy a specific formula ( During the cavitation process, tiny bubbles are formed inside the liquid, which burst rapidly to produce local high temperature and high pressure, changing the physical properties of the fuel. For fuels such as diesel, its dynamic viscosity will change from 12.5mm 2 / s down to 4.3mm 2 / s, thereby improving the fluidity of the fuel and making it easier for the subsequent atomization process. At the same time, the fuel modification effect satisfies a specific formula ( ), for example, the temperature of diesel is raised from −30°C to 80°C after pretreatment. This temperature increase also helps the atomization and mixing of the fuel.

[0124] Gradual heating: The fuel that has been treated with ultrasonic cavitation enters the graded heating system. The first-stage preheating module uses a PTC heater, which uses the characteristic of the PTC thermistor to generate heat when current passes through it to heat the fuel to 38℃~42℃, and the thermal efficiency reaches ≥93%. Then, the fuel enters the secondary precision temperature control module, which uses a semiconductor laser with a wavelength of 980mm for heating. The semiconductor laser generates lasers of a specific wavelength through stimulated radiation, and the laser energy is absorbed by the fuel to achieve heating, which is heated to 78℃~82℃, and the temperature control accuracy can reach ±0.5℃. A vortex generator is set between the two-stage modules, and its height is 1 / 5~1 / 3 of the flow channel diameter. The working principle of the vortex generator is to change the flow state of the fuel, so that the fuel produces a vortex, enhance the mixing and heat exchange inside the fuel, further improve the preheating effect of the fuel, and ensure that the fuel temperature is uniform and stable in an appropriate range, so as to prepare for subsequent injection.

[0125] Injection execution phase

[0126] Fuel injection: The pre-treated fuel enters the injection execution unit through the conical transition cavity. The cone angle of the conical transition cavity is 12°±0.5°, the aspect ratio is 3:1, and the inner wall is coated with a nano-composite coating. The coating is composed of C r3 C2-NiCr is used as the matrix material, and Al2O3-TiO2 core-shell structure nano additives with a particle size of 80nm to 120nm and an addition amount of 8% to 12% are added. This coating has the characteristics of a thickness of 50μm to 80μm, low porosity, and a small friction coefficient. It can reduce the energy loss and flow resistance of the fuel during the transition process and ensure that the fuel enters the injection execution unit smoothly. The injection execution unit is composed of an asymmetric nozzle array formed by laser cladding. The aperture of the nozzle array is gradiently distributed, satisfying a specific formula ( ), the diameter difference of adjacent nozzles changes from the center to the edge according to the nozzle number. The nozzle diameter in the center area is 0.10mm~0.14mm, and the nozzle diameter in the edge area is 0.16mm~0.2mm. The nozzle array satisfies the logarithmic spiral arrangement relationship ( ), by controlling the initial radius coefficient of the spiral (related to the diameter of the combustion chamber) and the spiral growth rate coefficient (the core parameter for controlling the distribution density of the nozzle holes, with a value range of 0.23mm≤a≤0.27mm, 0.12≤b≤0.18), the distribution of the nozzle holes is made more reasonable. At the same time, the axis of the nozzle hole forms an angle with the tangent of the combustion chamber. When injecting fuel, the fuel is ejected from nozzle holes of different diameters and angles, interacting with the tangential airflow of the combustion chamber to form a fuel injection trajectory that is more conducive to mixing. The inner wall of the nozzle channel is provided with a periodic micro-groove structure, with a groove depth of 18μm~22μm, a spacing of 48μm~52μm, an asymmetric trapezoidal groove cross-section, a leading edge inclination of 55°~65°, a trailing edge inclination of 30°~40°, and a surface Vickers hardness of ≥800 HV. This micro-groove structure can make the interaction between the fuel and the inner wall of the channel more complex during the fuel injection process, promote the breakage and atomization of the fuel, and improve the atomization quality of the fuel. The fuel injector is manufactured using the selective laser melting process. During the manufacturing process, the laser power is 280W±5%, the scanning speed is 800mm / s±5%, and the layer thickness is 30μm. After forming, it undergoes vacuum heat treatment and the residual stress is reduced to ≤50MPa, which ensures the accuracy and performance of the fuel injector and improves its reliability and service life.

[0127] Pressure dynamic adjustment stage

[0128] Pressure monitoring and feedback: The MEMS thin film sensor array of the dynamic pressure regulation unit monitors fuel pressure and other parameters in real time. The sensor array contains three groups of piezoresistive sensors with a range of 0MPa to 50MPa, short response time (≤0.25ms), small nonlinear error (≤0.05%FS), and low temperature drift coefficient (≤0.002%FS / ℃). The sensor transmits the measured real-time pressure data to the fuzzy neural network controller.

[0129] Pressure control algorithm execution: The fuzzy neural network controller adopts a 7-12-3 BP network topology. The input layer includes seven parameters: speed, load, intake temperature, oxygen concentration, injection pressure, injection pulse width and fuel viscosity. The controller executes a fourth-order pressure control algorithm ( ), according to the real-time pressure error ( ), the proportional, integral, differential coefficients of PID control and the working condition self-learning coefficient (the value range is 0.2≤α≤0.8, and it is dynamically adjusted through the fuzzy rule library), and the injection pressure adjustment amount is calculated. The training data set contains ≥105 sets of transient working condition data, the network convergence condition is mean square error MSE≤0.005, and the learning rate adaptive adjustment range is 0.01~0.1, which ensures that the controller can accurately and efficiently adjust the injection pressure according to different working conditions, so that the fuel injection pressure is always kept in the best state, ensuring the fuel atomization effect and combustion performance. The dynamic pressure regulation unit is electrically connected to the sensor array through a coaxial shielded signal line, and the shielding effectiveness of the coaxial shielded signal line is ≥60dB to ensure the stability and accuracy of signal transmission. The whole system has a short dynamic response time (≤35ms) and a small pressure fluctuation rate (≤3.8%). The average diameter of the Soter at −30°C is 18.7μm±0.5μm, and the standard deviation of the particle size distribution is ≤4.2μm, ensuring efficient and stable operation under different environmental conditions, improving the combustion efficiency and performance of the engine, and reducing pollutant emissions.

[0130] It should be noted that:

[0131] The same symbol has the same meaning in different claims (for example, ρ always represents fuel density).

[0132] All formulas are verified by dimensional consistency (e.g. the cavitation number σ is dimensionless).

[0133] Each parameter corresponds to a measurable or calibrable physical quantity (such as a, b determined by computational fluid dynamics (CFD) optimization).

[0134] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0135] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A high-efficiency atomizing injection system for a direct injection fuel injector, characterized in that: include: a) The injection execution unit is composed of an asymmetric nozzle array formed by laser cladding, and the nozzle array satisfies the logarithmic spiral arrangement relationship: r: radial distance from the nozzle center to the spiral origin, unit: mm; θ: polar angle corresponding to the nozzle position, unit: radian; a: initial radius coefficient of the helix, related to the diameter of the combustion chamber; b: Spiral growth rate coefficient, the core parameter controlling the distribution density of nozzle holes; The value range of parameter a is 0.23 mm ≤ a ≤ 0.27 mm, the value range of parameter b is 0.12 ≤ b ≤ 0.18, and the axis of the nozzle and the tangent of the combustion chamber form an angle of 15° to 19°; b) A dynamic pressure regulation unit, integrating a MEMS thin film sensor array and a fuzzy neural network controller, the controller executing a fourth-order pressure control algorithm: ΔP: injection pressure adjustment, unit: MPa; e(t): real-time pressure error, , unit: MPa; Kp, Ki, Kd: proportional, integral and differential coefficients of PID control; α: working condition self-learning coefficient, dynamically adjust the algorithm weight; Among them, the value range of the working condition self-learning coefficient is 0.2≤α≤0.8, and it is dynamically adjusted through the fuzzy rule base; c) Fuel pretreatment unit, including ultrasonic cavitation device and staged heating system, the ultrasonic cavitation device has an operating frequency of 25kHz to 30kHz and a power density of 12W / cm 2 ~18W / cm 2 , and the cavitation number σ satisfies: Where P υ is the saturated vapor pressure of fuel, P is the local static pressure, ρ is the fuel density, and V is the characteristic flow velocity; The injection execution unit is connected to the outlet of the fuel pretreatment unit through a conical transition cavity, the conical transition cavity has a cone angle of 12°±0.5° and a length-to-diameter ratio of 3:1, and the dynamic pressure adjustment unit is electrically connected to the sensor array through a coaxial shielded signal line, and the shielding effectiveness of the coaxial shielded signal line is ≥60dB.

2. According to claim 1, a high-efficiency atomizing injection system for a direct injection fuel injector in a cylinder, characterized in that: The apertures of the nozzle array are distributed in a gradient manner, satisfying: Wherein Δd is the diameter difference of adjacent nozzles, N is the nozzle number counted from the center to the edge, the nozzle diameter in the center area is 0.10 mm to 0.14 mm, and the nozzle diameter in the edge area is 0.16 mm to 0.2 mm.

3. According to claim 1, a high-efficiency atomizing injection system for a direct injection fuel injector in a cylinder, characterized in that: The inner wall of the injection nozzle channel of the injection execution unit is provided with a periodic micro-groove structure, the groove depth is 18μm to 22μm, the spacing is 48μm to 52μm, the groove cross-section is an asymmetric trapezoid, the leading edge inclination angle is 55° to 65°, the trailing edge inclination angle is 30° to 40°, and the surface Vickers hardness is ≥800 HV.

4. According to claim 1, a high-efficiency atomizing injection system for a direct injection fuel injector in a cylinder, characterized in that: The MEMS thin film sensor array of the dynamic pressure regulating unit includes three groups of piezoresistive sensors with a measuring range of 0MPa to 50MPa, a response time of ≤0.25ms, a nonlinear error of ≤0.05%FS, and a temperature drift coefficient of ≤0.002%FS / °C.

5. According to claim 1, a high-efficiency atomizing injection system for a direct injection fuel injector in a cylinder, characterized in that: The fuzzy neural network controller adopts a 7-12-3 BP network topology structure. The input layer includes seven parameters, namely, speed, load, intake temperature, oxygen concentration, injection pressure, injection pulse width and fuel viscosity. The training data set includes ≥105 groups of transient operating condition data. The network convergence condition is mean square error MSE≤0.005, and the learning rate adaptive adjustment range is 0.01 to 0.

1.

6. The high-efficiency atomizing injection system for a direct injection fuel injector according to claim 1, characterized in that: The hierarchical heating system comprises: First-stage preheating module: PTC heater is used to heat the fuel to 38℃~42℃, with thermal efficiency ≥93%; Secondary precision temperature control module: uses a semiconductor laser with a wavelength of 980mm to raise the temperature of the fuel to 78℃~82℃, with a temperature control accuracy of ±0.5℃, and a vortex generator is set between the two-stage modules, with a height of 1 / 5~1 / 3 of the flow channel diameter.

7. The high-efficiency atomizing injection system for a direct injection fuel injector according to claim 1, characterized in that: The inner wall of the tapered transition cavity is coated with a nanocomposite coating, and the coating composition is: Base material: C r3 C2-NiCr, mass ratio 7:3; Nano additives: Al2O3-TiO2 core-shell structure particles, particle size 80nm~120nm, addition amount 8%~12% matrix material; The coating thickness is 50μm to 80μm, the porosity is ≤0.5%, and the friction coefficient is ≤0.

18.

8. The high-efficiency atomizing injection system for a direct-injection fuel injector according to claim 1, characterized in that: The fuel modification effect of the ultrasonic cavitation device meets the following requirements: Where η is the fuel dynamic viscosity, T is the fuel temperature, A, B, C are the fuel physical constants calibrated by experiments, diesel: A = −3.2, B = 1200, C = 150, after pretreatment, T rises from −30 ° C to 80 ° C, η rises from 12.5 mm 2 / s down to 4.3mm 2 / s, and the atomization angle is maintained at 85°±2°.

9. The high-efficiency atomizing injection system for a direct injection fuel injector according to claim 3, characterized in that: The fuel injector is manufactured by a selective laser melting process, with a laser power of 280W±5%, a scanning speed of 800mm / s±5%, a layer thickness of 30μm, and a vacuum heat treatment at 1050℃×2h after forming, with a residual stress of ≤50MPa.

10. The high-efficiency atomizing injection system for a direct injection fuel injector according to claim 1, characterized in that: The system composed of the injection execution unit, the dynamic pressure regulation unit and the fuel pretreatment unit has a dynamic response time of ≤35ms, a pressure fluctuation rate of ≤3.8%, a Sauter mean diameter of 18.7μm±0.5μm under a −30°C environment, and a particle size distribution standard deviation of ≤4.2μm.

Images