A method for processing and performance debugging of fuel nozzle

Abstract

The application discloses a fuel nozzle processing and performance debugging method, comprising the following steps: S1, processing and optimization of a sub-oil path nozzle and a swirler; S2, processing technology optimization of a nozzle rod and an assembly; S3, matching analysis on fuel nozzle flow; and S4, after welding of parts, tightening is carried out by using a torque wrench, and the tightening torque is gradually adjusted, and the reliability of the torque is verified through test; the method effectively improves the processing quality and stability of the sub-oil path swirler, reduces the influence of welding thermal deformation, improves the stability of the main oil path flow, and greatly improves the product qualification rate.

Description

Technical Field

[0001] This invention belongs to the field of fuel nozzle processing and testing technology, and in particular, relates to a method for processing and adjusting the performance of fuel nozzles. Background Technology

[0002] The Type 1 fuel injector is a new generation of welded, complex dual-circuit fuel injector, composed of various individual components such as the injector rod, auxiliary fuel line nozzle, auxiliary fuel line swirler, screw plug, cap, and filter screen. Unlike other dual-circuit fuel injectors that have an independent main nozzle, this fuel injector integrates the main nozzle into the injector rod, resulting in better overall injector integrity. However, this also means that there are more machining areas for each individual component, leading to greater machining and performance tuning challenges.

[0003] The main challenges in manufacturing this fuel nozzle lie in the following aspects:

[0004] Machining difficulties: The machining process involves the use of numerous micro-tools, and the precision dimensional machining is unstable due to the influence of the tools and machining parameters, which greatly affects the performance of the fuel nozzle; secondly, the main nozzle is concentrated in the nozzle rod, and the tool deflection is severe during machining due to the clamping method, and the high requirements for dimensional accuracy and surface quality place high demands on the tools, resulting in high machining difficulty;

[0005] Performance debugging is difficult: The auxiliary fuel circuit flow rate is unstable. The auxiliary fuel circuit flow rate is jointly controlled by the auxiliary fuel circuit nozzle and the auxiliary fuel circuit cyclone separator. Since the connection between the auxiliary fuel circuit nozzle and the cyclone separator is a clearance fit, some fuel will flow out from the gap, resulting in an unstable overall flow rate. Secondly, the auxiliary fuel circuit flow rate is too high. Due to the influence of the precision dimensional machining stability of the auxiliary fuel circuit nozzle and the main nozzle assembly, it is difficult to control the main fuel circuit flow rate within the qualified range. At the same time, the main fuel circuit flow rate is significantly affected by welding heat.

[0006] Patent application CN110421316A discloses a novel process for processing fuel nozzles. By improving the processing method, it eliminates the heat-affected zone around the nozzle, effectively removing the specified material while leaving a heat-free interface. This significantly improves the surface properties of the nozzle wall, enhancing accuracy and precision. The nozzle achieves extremely high surface finish, with a roughness of Ra≤0.1μm, resulting in excellent performance. Furthermore, the nozzles exhibit good consistency, with the roundness, cylindricity, taper, and roughness of the machined, clean holes showing high uniformity. However, this patent requires roughing, semi-finishing, and finishing processes to ensure dimensional accuracy for each part. The patent emphasizes that the roughing and finishing of the same batch of parts should be spaced out over a period of time. Therefore, the process involves repeated clamping of parts, and errors from these repeated clamping operations can affect the processing accuracy of the same batch, making it difficult to guarantee the consistency of nozzle performance. Furthermore, this nozzle is a single-oil-path combined centrifugal nozzle, which has a relatively simple structure and its performance matching complexity is not as high as that of the welded dual-oil-path centrifugal nozzle. Summary of the Invention

[0007] This invention addresses the problem in existing technologies where the main nozzle of a fuel injector is integrated into the nozzle rod, resulting in better overall nozzle integrity but more machining parts for each component, leading to greater machining and performance tuning difficulties and a lower pass rate for machined parts. The invention provides a method for machining and tuning fuel injectors.

[0008] To address the aforementioned technical problems, the technical solution of the present invention is as follows:

[0009] A method for processing and adjusting the performance of a fuel injector includes the following steps:

[0010] S1. Machining optimization of auxiliary oil passage nozzles and cyclones: Based on the geometry of the parts, the auxiliary oil passage nozzles are precision machined using an internal turning tool, a contour sub-drill, and a forming grinding head, respectively; Machining optimization of auxiliary oil passage nozzles and cyclones: Based on the geometry of the parts, the auxiliary oil passage nozzles are precision machined using an internal turning tool, a contour sub-drill, and a forming grinding head, respectively; The machining parameters of the micro-milling cutter used to machine the cyclone grooves are optimized, and burrs on the cyclone grooves are removed;

[0011] S2. Nozzle rod assembly machining optimization: Add process holes and convert the blank datum to the process hole location;

[0012] S2.1 Based on the structural characteristics of the nozzle rod, an auxiliary support structure and a double-top structure are added to the fixture;

[0013] S2.2. The machining was carried out by using a CNC lathe and a vertical machining center respectively. According to the internal cavity structure and machining requirements of the main nozzle, a tapered milling cutter was used to rough and finish the 74° tapered surface of the nozzle rod assembly. A forming reamer was used to finish the 110° inner tapered surface and the φ7.8 inner hole of the nozzle rod assembly.

[0014] S3. Analyze the matching performance of fuel nozzle flow. Before the flow test, measure and number the key dimensions of the nozzle rod assembly, auxiliary fuel line nozzle and auxiliary fuel line swirler, and then select them in sequence for flow test. Select the auxiliary fuel line nozzle or auxiliary fuel line swirler according to the flow test results.

[0015] S4. After the parts are welded, tighten them with a torque wrench and gradually adjust the tightening torque. Verify the reliability of the torque through testing.

[0016] Furthermore, in step S1, a contour-following sub-drill is selected as the finishing tool.

[0017] Furthermore, the cutting edge of the contour-following drill is a single-edged type, and the rotational speed is 12000 r / min with a feed rate of F10.

[0018] Furthermore, in step S1.1, the machining parameters of the micro-milling cutter are optimized using a tool monitoring system. Sensors are installed on the A-axis and C-axis of the machine tool, and the data is collected in real time through a data acquisition system to determine whether the tool is experiencing any abnormalities.

[0019] Furthermore, the sensor is a resonant acoustic emission sensor, and the micro-milling cutter machining parameters are a rotational speed of 25,000 r / min, a feed rate of 10 mm / min, and a cutting depth of 0.1 mm.

[0020] Furthermore, in step S1.1, during the process of removing burrs from the vortex groove, the outer circle of the vortex groove is first precision machined to remove the burrs on the surface, and then a chamfering cutter is used for machining. The machining path of the chamfering cutter is consistent with the machining path of the micro-milling cutter.

[0021] Furthermore, in step S2.1, the auxiliary support structure is located at the bottom of the main nozzle, and the double-top structure is located at the middle rod position of the nozzle.

[0022] Furthermore, in step S2.2, during the machining of the CNC nozzle rod assembly, a counterweight is added to the main nozzle side of the CNC fixture so that after the part is installed, the center of gravity of the CNC fixture is located on the rotation center.

[0023] Further, in step S2.2, the 74° conical surface is rough machined using a φ8.5 taper end mill, and then the 74° conical surface is finished using a φ10 taper end mill; the 110° inner cone and the φ7.8 inner hole are finished using a φ7.8 forming reamer.

[0024] Furthermore, in step S3, the fitting clearance between the nozzle rod assembly and the auxiliary oil passage nozzle is 0.010 to 0.015 mm, and the fitting clearance between the auxiliary oil passage nozzle and the cyclone separator is 0.011 mm to 0.016 mm.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. This invention tested internal turning tools, profile grinding heads, and profile sub-drills for machining the secondary oil passage nozzle. After comparative analysis, the profile sub-drill produced the best and most stable surface quality of the inner cone. The optimal parameters for profile sub-drilling were determined to be a rotational speed of 12000 r / min and a feed rate of F10. For the secondary oil passage cyclone separator, the machining parameters of the φ0.3 micro-end mill were optimized using a tool monitoring system. The optimal parameters for the φ0.3 end mill were determined to be a rotational speed of 25000 r / min, a feed rate of 10 mm / min, and a depth of cut of 0.1 mm, effectively improving the machining quality and stability of the secondary oil passage cyclone separator.

[0027] 2. This invention optimizes the machining process of the nozzle rod and its components, improves the datum conversion process, and adds process positioning holes for datum conversion, thereby reducing repeated clamping errors and improving the dimensional accuracy rate. Furthermore, based on the structural characteristics of the nozzle rod, it optimizes the fixture, improves the clamping scheme, and adds auxiliary support structures and a double-top structure to eliminate the problem of positional deviations in the parts during machining.

[0028] 3. During the fuel injector debugging process, by selecting appropriate processes, the matching relationship between the injector rod assembly, auxiliary fuel line nozzle, and cyclone separator was determined, reducing the number of rework adjustments and increasing the first-time assembly flow rate qualification rate of fuel injectors from 0 to 58.8%. The adoption of a torque wrench assembly process increased the tightening torque, effectively reducing the impact of welding thermal deformation and improving the stability of the main fuel line flow rate. Through a series of process improvements, the qualification rate increased by more than 50%. Attached Figure Description

[0029] Figure 1 This is a flowchart of the fuel nozzle rod processing and performance debugging method of the present invention;

[0030] Figure 2 This is a flowchart illustrating the matching analysis of fuel nozzle flow rates according to the present invention.

[0031] Figure 3 This is a schematic diagram of the welded dual-oil-circuit fuel nozzle structure of the present invention;

[0032] Figure 4 This is a monitoring signal diagram of the milling process of the auxiliary oil circuit cyclone separator of the present invention;

[0033] Figure 5This is a schematic diagram of the countersinking process of the nozzle rod 30 according to the present invention;

[0034] Figure 6 This is a schematic diagram of the optimized fixture structure of the present invention;

[0035] Figure 7 This is a schematic cross-sectional view of the optimized fixture structure of the present invention;

[0036] Table 1 is a schematic diagram of the CNC vertical machining tool scheme for the nozzle rod of the present invention;

[0037] Table 2 shows the test data after the selected combinations of the present invention;

[0038] Table 3 shows the fuel nozzle flow test data of the present invention;

[0039] In the above figure, 1. Nozzle rod assembly; 2. Auxiliary oil passage nozzle; 3. Auxiliary oil passage cyclone separator; 4. Mounting hole; 5. Auxiliary support structure; 6. Double top structure; 7. Plug; 8. Plug; L1: Countersunk hole depth; L2: Mounting edge height; φA: Countersunk hole diameter. Detailed Implementation

[0040] To clearly illustrate the technical features of the present invention, the present invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present application; however, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below. Furthermore, it should be understood in the description of this application that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present application. In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0041] Example 1

[0042] like Figure 1As shown, a method for processing and adjusting the performance of a fuel injector includes the following steps:

[0043] S1. Optimization of machining of auxiliary oil passage nozzle and cyclone separator: Based on the geometry of the part, the auxiliary oil passage nozzle 2 is precision machined using an internal turning tool, a contour drill, and a forming grinding head; the machining parameters of the micro-milling cutter for machining the cyclone groove are optimized, and the burrs on the cyclone groove are removed.

[0044] S2. Nozzle rod and component processing optimization: Add process holes and convert the blank datum to the process hole location;

[0045] S2.1 Based on the structural characteristics of the nozzle rod, the fixture structure and clamping scheme are optimized by adding auxiliary support structure 5 and double-top structure 6;

[0046] S2.2. The machining was carried out by using a CNC lathe and a vertical machining center respectively. According to the internal cavity structure and machining requirements of the main nozzle, a tapered milling cutter was used to rough and finish the 74° tapered surface of the nozzle rod assembly 1. A forming reamer was used to finish the 110° inner tapered surface and the φ7.8 inner hole of the nozzle rod assembly.

[0047] S3. Analyze the matching performance of fuel nozzle flow rate. Before the flow test, measure and number the key dimensions of nozzle rod assembly 1, auxiliary fuel line nozzle 2 and auxiliary fuel line swirler 3, and then select them in sequence for flow test. Select auxiliary fuel line nozzle 2 or auxiliary fuel line swirler 3 according to the flow test results.

[0048] S4. After the parts are welded, tighten them with a torque wrench and gradually adjust the tightening torque. Verify the reliability of the torque through testing.

[0049] In this embodiment, the machining process of the auxiliary oil passage nozzle 2 is optimized: the main machining difficulty of the auxiliary oil passage nozzle 2 lies in the machining of the φ0.4 inner hole and the 60° inner cone, such as... Figure 3 As shown, the machining accuracy and quality of this part directly affect the spray cone angle of the auxiliary oil circuit. In the finishing process, internal turning tools, forming grinding heads and contour drilling were tested respectively.

[0050] Among these, the internal turning tool is relatively slender, with a tip of only about 0.2mm, making tool setting difficult and the tip prone to chipping. The tool rigidity is insufficient, and the internal cone has a large allowance, causing the internal turning tool to break when machining to 1 / 3 of the cone surface. The forming grinding head is in complete contact with the cone surface of the part. Due to the high viscosity of stainless steel, it heats up quickly, resulting in significant grinding heat and difficulty for coolant to enter, leading to severe grinding head wear. The worn grinding head produces inconsistent grinding quality and unstable surface finish. The profile submerged drill has a single-edge cutting edge design, which, compared to traditional profile submerged drills, facilitates coolant entry into the cutting environment. Through testing with various cutting parameters, at a speed of 12000 r / min and a feed rate of F10, the surface quality of the cone surface was significantly improved.

[0051] By comparing and analyzing the three processing methods, the surface quality of the parts processed by contour drilling is the best and most stable.

[0052] like Figure 4 As shown, in this embodiment, the machining process of the auxiliary oil circuit cyclone separator 3 is optimized: the cyclone grooves of the cyclone separator are machined using a φ0.3 milling cutter. Because the milling cutter is relatively small and has poor rigidity, the machining dimensions are unstable. Therefore, a tool monitoring system is used to optimize the machining parameters of the φ0.3 milling cutter. Resonant acoustic emission sensors for monitoring acoustic emission signals are installed on the A-axis and C-axis of the machine tool to monitor the acoustic emission signals during the milling process. These signals are then collected in real time by a data acquisition system to determine if any abnormalities such as tool breakage or tool damage occur. The optimal parameters for the φ0.3 milling cutter are: rotational speed 25000 r / min, feed rate 10 mm / min, and depth of cut 0.1 mm.

[0053] In this embodiment, burrs on the surface of the vortex groove are removed manually, and then removed by CNC. That is, by optimizing the program, CNC is used to remove burrs. After machining the vortex groove, the outer circle of the vortex groove is first finished with an external turning cutter to remove the burrs on the surface. Then, a chamfering cutter is used for machining. The machining path of the chamfering cutter is consistent with the machining path of the φ0.3 milling cutter to remove burrs on the edge of the vortex groove.

[0054] Example 2

[0055] like Figure 1 As shown, a fuel nozzle machining and performance debugging method is described. In this embodiment, the reference conversion process is optimized: three Φ6.4 mounting holes 4 are machined on the nozzle mounting surface, and a 3mm machining allowance is left at the top of the mounting holes 4. When machining the M5 thread in process 30, a countersunk hole is machined above the thread to convert the blank reference to the three countersunk holes. The upper part of the hole is used for positioning and angular determination when machining the Φ6.4 mounting hole in process 90, and the lower part of the hole is machined with an M5 thread for tightening and fixing the mounting surface in process 50.

[0056] Since the dial indicator head used for alignment has a diameter of 0.5mm, if the length of L1 is too short, the 90-degree alignment of the inner hole will be inconvenient. If the dial indicator head hits the hole opening, it may also cause a large installation error. If the length of L1 is too long, the thread length (L2-L1) becomes smaller, the number of thread turns decreases, and there is a risk of inner hole thread deformation under high tension. Because a 2mm machining allowance is left on the support surface, and the screw and threaded hole must have at least 4-5 threads to ensure the part will not loosen during clamping, considering all the above factors, if... Figure 5As shown, L2 can be 9mm and L1 can be 2mm, resulting in a thread hole depth of 7mm. After removing the 2mm machining allowance, the thread depth is still 5mm, and the number of thread turns is 6, ensuring that the part will not loosen during clamping and machining. In process 90, three ΦA holes can be directly located to achieve positioning and angular orientation, avoiding the need to find the blank datum again in process 90, thus achieving datum conversion.

[0057] Clamping process optimization: such as Figure 6 and Figure 7 As shown, an auxiliary support 5 is added to the bottom of the main nozzle to prevent the part from moving up and down when milling the end face, and a double-top structure 6 is added at the middle rod position to increase the stability of the part, prevent left and right swaying when milling the outer circle, and eliminate vibration marks.

[0058] Optimization of the machining process for nozzle rod assembly 1 (CNC turning): The nozzle rod is an irregularly shaped structural component, with its main structure concentrated on the mounting edge. The part's center of gravity is offset from the mounting edge. When machining the main nozzle using a CNC lathe, the part experiences significant centrifugal force after rotation, and the rotational speed cannot be increased, affecting machining accuracy. The CNC lathe fixture was optimized by adding two counterweights to the main nozzle side of the fixture. This ensures that after the part is mounted, the center of gravity of the entire fixture is located at the rotation center, eliminating the influence of centrifugal force. Employing a multi-layer, small-feed cutting method effectively ensures the machining quality of the conical surface and the smooth transition between the φ7.8 inner hole and the 110° cone, achieving one-time machining of the entire internal oil passage.

[0059] Optimization of the machining process for nozzle rod assembly 1 (CNC vertical machining): The cutting tool scheme for vertical machining of the nozzle rod is shown in Table 1. The 74° cone is the oil sealing surface. A φ8.5 taper end mill is used for rough machining of the 74° inner cone, leaving a 0.05mm allowance for finishing. Then, a φ10 taper end mill is used for finishing machining of the 74° inner cone. This not only ensures the dimensions of the inner cone but also improves the surface quality. A φ7.8 forming reamer is used at 110° to simultaneously finish both the 110° inner cone and the φ7.8 inner hole. This ensures the consistency of the inner hole and eliminates tool marks at the transition between the inner cone and the hole, thus eliminating the impact of tool marks on fuel flow.

[0060] Table 1

[0061]

[0062] Example 3

[0063] As shown in Table 2, in this embodiment, the inner diameter φ3.2 of the auxiliary oil passage nozzle 2, the outer diameter φ3.2 of the auxiliary oil passage cyclone separator 3, the inner diameter φ7.8 of the nozzle rod assembly 1, and the outer diameter φ7.8 of the auxiliary oil passage nozzle 2 were measured, and the parts were numbered and the measured values ​​were recorded.

[0064] Table 2

[0065]

[0066] The required range for the main oil circuit flow rate is 1115.9–1161.5 g / min. When the fitting clearance is 0.01 mm, the main oil circuit flow rate is 1117.6 g / min, which is slightly higher than the lower limit. When the fitting clearance is 0.015 mm, the main oil circuit flow rate is 1141.2 g / min, which is slightly higher. Based on the experience in developing fuel nozzles, the main oil circuit flow rate will be higher after welding. Therefore, based on the flow rate value, the fitting clearance between the nozzle rod 1 assembly and the auxiliary oil circuit nozzle 2 can be combined between 0.010 and 0.015 mm. In this example, a fitting clearance of 0.012 mm is more appropriate.

[0067] The flow rate of the auxiliary oil circuit ranges from 128.8 to 135.4 g / min. When the auxiliary oil circuit cyclone separator 3 is fitted with the auxiliary oil circuit nozzle 2, the fitting clearance is 0.007 mm, and the flow rate of the auxiliary oil circuit is 125.3 g / min, which is less than the design requirement. When the fitting clearance increases to 0.010 mm, the flow rate of the auxiliary oil circuit is 128.1 g / min, which is slightly less than the design value. Only minor repairs to the cyclone separator are needed to achieve the required result. When the fitting clearance is 0.016 mm, the flow rate of the auxiliary oil circuit is 134.5 g / min, which is slightly above the design requirement. Therefore, the fitting clearance between the auxiliary oil circuit nozzle 2 and the auxiliary oil circuit cyclone separator 3 should be selected between 0.011 mm and 0.016 mm. In this example, a fitting clearance of 0.012 mm is more suitable.

[0068] As shown in Table 2, among the selected fuel nozzles, 10 pieces had both main and auxiliary fuel lines that passed the test, resulting in a first-time assembly pass rate of 58.8%. This method can improve the first-time assembly flow test pass rate while reducing the number of parts repairs. During repairs, the repair values ​​can be quantified, reducing the reliance on manual skill levels during fuel nozzle debugging.

[0069] After the nozzle parts are welded, they are tightened using a torque wrench, and the tightening torque is gradually adjusted. The reliability of the torque is verified through testing. See Table 3 for details.

[0070] Table 3

[0071]

[0072] When the torque is 20 N·m, comparing the flow test data before and after welding, the flow rate of the main oil circuit before and after welding varies, with the maximum change being 12.4 g / min. After tightening with a torque wrench, the flow rate of the main oil circuit after welding is significantly stable.

[0073] Obviously, the embodiments described above are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method of fuel nozzle machining and performance tuning, characterized by, The method comprises the following steps: S1, the vice oil way spout and the cyclone processing optimization: according to the geometry of the parts, respectively try to use the hole turning tool, the profiled drill and the finishing grinding head to finish the vice oil way spout; the processing parameters of the micro milling cutter for processing the cyclone groove are optimized, and the burrs on the cyclone groove are removed; the tool monitoring system is used to optimize the micro milling cutter processing parameters, the sensor is installed on the A axis and C axis of the machine tool, and then the data acquisition system is used to collect and monitor the acoustic emission signals in the milling process in real time to determine whether the tool is abnormal; wherein the sensor is a resonant acoustic emission sensor, and the micro milling cutter processing parameters are 25000r / min, 10mm / min and 0.1mm; S2, the nozzle rod assembly processing optimization: increase the process hole, and convert the blank reference to the process hole; S2.1, based on the structure characteristics of the nozzle rod assembly, an auxiliary support structure and a double top structure are added on the clamp; S2.2, respectively try to use the numerical control lathe and the vertical machining center for processing, and according to the internal cavity structure of the main nozzle and the processing requirements, select the taper milling cutter to respectively rough and finish the 74° taper surface of the nozzle rod assembly, and select the profile reamer to finish the 110° internal taper and φ7.8 internal hole of the nozzle rod assembly; φ8.5 taper milling cutter is used to rough the 74° taper surface, φ10 taper milling cutter is used to finish the 74° taper surface, and φ7.8 profile reamer is used to finish the 110° internal taper and φ7.8 internal hole; S3, the fuel nozzle flow matching analysis, the key dimensions of the nozzle rod assembly, the vice oil way spout and the vice oil way cyclone are measured and numbered before the flow test, and then the flow test is selected in turn, and the vice oil way spout or the vice oil way cyclone is selected according to the flow test result; S4, after the parts are welded, use the torque wrench to tighten, and gradually adjust the tightening torque, and verify the reliability of the torque through the test.

2. A method of fuel nozzle machining and performance tuning according to claim 1, wherein, In the step S1, the profiled drill is selected as the finishing tool.

3. A method of fuel nozzle machining and performance tuning according to claim 2, wherein, The cutting edge of the profiled drill is single blade.

4. The method of claim 1 wherein, In the step S1, during the process of removing the burrs of the cyclone groove, the outer circle of the cyclone groove is first finished, and the burrs on the surface are removed, and then a chamfering tool is used for processing, and the processing path of the chamfering tool is consistent with that of the micro milling cutter.

5. The method of claim 1 wherein, In the step S2.1, the auxiliary support structure is arranged at the bottom of the main nozzle, and the double top structure is arranged at the middle rod position of the nozzle.

6. A method of fuel nozzle machining and performance tuning as defined in claim 1, wherein, In the step S2.2, during the process of machining the nozzle rod assembly by numerical control lathe, a counterweight is added to the main nozzle side of the numerical control lathe clamp, so that the center of gravity of the numerical control lathe clamp is located on the rotation center after the part is installed.

7. The method of claim 1 wherein, In the step S3, the fitting gap between the nozzle rod assembly and the vice oil way spout is 0.010-0.015mm, and the fitting gap between the vice oil way spout and the cyclone is 0.011mm-0.016mm.

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