A fuel step rapid injection device and injection method

Abstract

The application discloses a fuel step rapid injection device and injection method, and belongs to the field of aero-engine whole machine test, and aims at solving the problems of complex system, high cost, low injection precision and slow response. The device comprises a servo motor, a screw pair, an oil injector, first and second remote switch valves, first and second check valves and a safety valve. The servo motor drives the oil injector piston rod through the screw pair, the oil injector rod cavity is connected with the low-pressure fuel system through the second remote switch valve, and is connected with the engine fuel manifold through the first remote switch valve and the first check valve. A bypass connected with the fuel control device through the second check valve is arranged between the first check valve and the fuel manifold. In normal operation, the fuel control device supplies fuel to the fuel manifold through the second check valve; in step injection, the second remote switch valve is opened, the piston rod is extended to suck oil, then the piston rod is closed, the first remote switch valve is opened, and the piston rod is quickly retracted to inject fuel into the manifold. The application can be used in aero-engine surge test.

Description

Technical Field

[0001] This invention relates to the field of aero-engine whole-machine testing, specifically to a fuel step rapid injection device and injection method. Background Technology

[0002] Accurately obtaining the stability margin of the high-pressure compressor under simulated flight conditions is crucial during ground testing of the entire aero-engine. A rapid fuel injection surge test is one effective method for obtaining this margin. Its basic principle is as follows: Under stable engine operation, a certain amount of additional fuel is injected into the combustion chamber via a dedicated system within a very short time. This fuel participates in combustion instantaneously, causing a sharp rise in gas temperature, which in turn raises the temperature in front of the worm gear, causing the high-pressure compressor's operating line to rise towards the surge boundary. Due to the large moment of inertia of the high-pressure rotor, its rotational speed does not change significantly in a short period. Therefore, the high-pressure compressor's operating point will rapidly move towards the surge boundary along the constant speed line on the characteristic diagram. When the injected fuel amount reaches a certain critical value, the compressor's operating line will coincide with the surge boundary, thus triggering compressor surge. By precisely controlling the injected fuel amount and recording the critical point of surge, the stability margin of the high-pressure compressor under the current operating condition can be calculated.

[0003] To successfully implement a rapid fuel injection step-injection test, the injection system itself must possess extremely high response speed and precise flow control capabilities. Currently, the commonly used rapid fuel injection step-injection device technology in this field in China is as follows: This system is typically independent of the engine's main fuel system. Its main components include a dedicated high-pressure fuel pump station, a high-speed solenoid valve, and a high-pressure pipeline connecting the two. The high-pressure fuel pump station continuously generates and stores fuel at pressures higher than the engine's normal operating pressure, providing the pressure source for the step-injection. The high-speed solenoid valve is installed on the pipeline between the outlet of the high-pressure fuel pump station and the inlet of the engine's fuel mains, serving as the actuator of the entire system. During the step-injection test, the control system sends an opening command to the high-speed solenoid valve, which opens instantaneously. The high-pressure fuel stored in the high-pressure fuel pump station is then injected instantaneously into the engine's fuel mains through the pipeline, achieving a step-increase in fuel flow. When the injection volume reaches a preset value, the control system instructs the solenoid valve to close rapidly, completing one step-injection.

[0004] However, with the continuous development of aero-engine technology, the new generation of engines has placed higher demands on the response time and flow accuracy of fuel step injection, and the limitations of the existing technical solutions are becoming increasingly apparent, mainly in the following aspects: 1. Slow injection speed More importantly, the inherent opening and closing delays of the solenoid valves and their actuation methods used in existing systems, along with the fuel transmission delay in long pipelines, collectively limit the speed of fuel step injection. For the fuel step injection required by next-generation engines to be completed in milliseconds or even shorter, the response time of existing systems can no longer meet the testing requirements, which directly restricts the accuracy and effectiveness of surge margin testing for new engines.

[0005] II. Low precision in oil injection volume control Existing technologies offer relatively low precision in controlling fuel injection volume. The injection volume is typically controlled by manipulating the opening duration of the solenoid valve and maintaining the outlet pressure of the high-pressure pump station—an open-loop control method. However, the response characteristics of the solenoid valve are inconsistent, and factors such as pressure fluctuations in the pipeline and the compressibility of the fuel affect the actual volume of fuel passing through. This makes it difficult to achieve precise and repeatable control of the final fuel injection volume into the engine, a significant drawback for tests requiring accurate measurement of surge boundaries.

[0006] III. Safety hazards exist in the injection process. The existing system does not actively protect against the risk of overpressure during the injection process. If the control fails, it may cause a fire or engine surge and stall, posing a serious safety hazard.

[0007] IV. The system is complex and costly. Existing fuel injection step injection schemes use high-pressure fuel pump stations in conjunction with solenoid valves to achieve step injection. The system configuration is relatively complex, requiring a dedicated high-pressure fuel pump station and its associated pressure regulation, energy storage, and cooling equipment, resulting in high construction costs and a large footprint. This places a heavy economic burden on the construction and operation of the laboratory.

[0008] Therefore, there is an urgent need in this field for a fuel injection device that features fast fuel injection speed, precise control of injection volume, safe injection process, simple structure, and controllable cost. Summary of the Invention

[0009] Based on the above analysis, the present invention aims to provide a fuel step rapid injection device and injection method to solve one of the technical problems in the prior art, such as slow injection speed, low fuel injection volume control accuracy, safety hazards in the injection process, and complex and costly system.

[0010] The objective of this invention is mainly achieved through the following technical solutions: This invention provides a fuel step rapid injection device, comprising: a servo motor, a fuel injector, a first remote switching valve, and a first check valve; The injector has a variable-volume chamber; The servo motor is used to drive the volume chamber of the oil injector to cyclically change between increasing and decreasing; The volume chamber is connected to the first remote switching valve and the first check valve in sequence through pipelines, and finally connected to the engine fuel main pipe; When a step-fast fuel injection is performed, the servo motor drives the volume chamber to decrease rapidly, so that the fuel in the volume chamber is pressurized and injected into the engine fuel manifold through the first remote switching valve and the first one-way valve, thereby realizing a step-fast fuel injection.

[0011] Furthermore, the oil injector adopts a single-rod piston hydraulic cylinder, and its rodless chamber is the volumetric chamber.

[0012] Furthermore, the oil injector is a plunger-type hydraulic cylinder, and its cavity is the volumetric cavity.

[0013] Furthermore, it also includes a second pressure sensor, which is disposed on the pipeline between the first check valve and the engine fuel manifold, for monitoring changes in fuel pressure entering the engine fuel manifold.

[0014] Furthermore, the servo motor drives the volume chamber of the oil injector to change via a helical pair.

[0015] Furthermore, the helical pair adopts a combination of a reducer and a ball screw mechanism.

[0016] Furthermore, the helical pair adopts a worm gear mechanism.

[0017] Furthermore, a bypass passage is provided between the first one-way valve and the engine fuel main pipe, and a second one-way valve is provided on the bypass passage. The second one-way valve is connected to the engine fuel control device. When the engine is working normally, the pressurized fuel of the engine fuel control device flows automatically into the engine fuel main pipe through the second one-way valve.

[0018] Furthermore, the injector is equipped with a displacement sensor to monitor the displacement of its piston rod. By monitoring the displacement change of the injector piston rod, the output fuel quantity of the rodless chamber of the injector can be accurately calculated.

[0019] Furthermore, it also includes a first pressure sensor and a second remote switching valve. The first pressure sensor is installed on the pipeline between the rodless chamber of the injector and the first remote switching valve to monitor the fuel pressure at the injector outlet. The second remote switching valve is installed on the bypass between the volume chamber and the first pressure sensor, and the second remote switching valve is connected to a low-pressure fuel supply system, enabling the fuel step injection device to achieve continuous multiple fuel step injections. The low-pressure fuel supply system is a fuel depot or a fuel pump station, wherein the low-pressure fuel is air-free fuel.

[0020] Furthermore, the fuel step rapid injection device also includes a safety valve, which is installed in the bypass between the first pressure sensor and the first remote switching valve to protect the system from overpressure. When the pressure in the pipeline exceeds the set threshold of the safety valve, the fuel in the pipeline overflows through the safety valve. The outlet of the safety valve is provided with a collection device for collecting the overflowed fuel.

[0021] Furthermore, the present invention also provides a fuel step rapid injection method, wherein the aforementioned fuel step rapid injection device performs fuel step rapid injection.

[0022] Furthermore, the aforementioned rapid fuel injection step method includes the following steps: S1: The fuel injection circuit of the fuel step injection device under normal operating conditions is physically isolated from the engine fuel main; S2: After the injector's volume chamber is filled with oil, the passage between the injector and the low-pressure fuel source is cut off. S3: Open the first remote switching valve, and the servo motor drives the fuel injector to achieve high-pressure fuel injection and step triggering; S4: Precise injection volume is achieved by controlling the displacement of the injector piston rod; S5: After injection is complete, the system is reset and returns to step S2 to achieve continuous injection.

[0023] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: I. Significantly improved fuel injection speed in a stepwise manner This invention employs a servo motor to directly drive the fuel injector. The servo motor has extremely high dynamic response characteristics, enabling rapid start-up and reverse acceleration / deceleration. This avoids the inherent opening and closing delays of solenoid valves in existing technologies, while also reducing the transmission delay of high-pressure fuel in long pipelines. This allows fuel to be squeezed from the rodless chamber of the fuel injector and injected into the engine fuel manifold at a near-instantaneous speed, achieving millisecond-level rapid fuel injection and fully meeting the stringent requirements of next-generation engines for injection response speed.

[0024] II. Precise control and metering of oil injection volume This invention utilizes a high-precision displacement sensor mounted on the injector to monitor the piston rod displacement in real time. Combined with the cross-sectional area of ​​the rodless chamber, it can accurately calculate the theoretical fuel displacement for each injection action, achieving precise control of the injection process. Simultaneously, by installing a safety valve with a pressure threshold on the pipeline and a collection device at its outlet, when system overpressure causes the safety valve to open, the overflowing fuel is collected and measured. By calculating the difference between the theoretical fuel displacement and the safety valve overflow, the precise amount of fuel actually injected into the engine can be obtained. This closed-loop metering method fundamentally solves the problem of poor accuracy in existing open-loop control technologies.

[0025] III. The system has multiple security protection capabilities. This invention utilizes a safety valve with a pressure threshold installed in parallel on the pipeline. When the pipeline pressure abnormally exceeds the limit due to an unexpected system malfunction, the safety valve automatically opens to release pressure, preventing damage to downstream critical equipment such as the engine fuel main and pressure sensors from high pressure, thus providing reliable overpressure protection. Furthermore, a second check valve installed on the bypass line between the engine fuel control unit and the fuel main automatically closes under high pressure during step fuel injection, reliably preventing high-pressure fuel from flowing back to the fuel control unit and protecting this precision component. These two protection mechanisms together enhance the overall safety of the system.

[0026] IV. The system structure is simplified, and the cost is significantly reduced. This invention replaces the complex and expensive high-pressure fuel pump station and its associated pressure regulating, energy storage, and cooling equipment in existing technologies with an electromechanical integrated drive unit consisting of a servo motor, a screw pair, and a fuel injector. This drive unit directly converts electrical energy into the driving force of high-pressure fuel, eliminating the need for a large pump station system and complex piping layout. This significantly simplifies the overall system structure, substantially reduces manufacturing costs and laboratory space requirements, and effectively solves the problems of complexity and high cost associated with existing technologies.

[0027] V. The system can perform multiple injections consecutively. This invention connects the rodless chamber of the injector to the low-pressure fuel supply system via a second remote switching valve. After completing one injection cycle, the system can open the second remote switching valve, extending the piston rod to draw fuel back into the low-pressure system, preparing for the next injection. This design allows for multiple consecutive step injections of fuel without complex fuel replenishment equipment, meeting the requirements of repeated testing in breath-force tests.

[0028] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0029] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0030] Appendix Figure 1 This is a schematic diagram of the fuel step rapid injection device of the present invention.

[0031] Explanation of reference numerals in the attached figures: 1-Servo motor; 2-Oil injector; 3-First pressure sensor; 4-Screw pair; 5-First remote switching valve; 6-Second pressure sensor; 7-First check valve; 8-Second check valve; 9-Safety valve; 10-Second remote switching valve; 11-Displacement sensor. Detailed Implementation

[0032] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of the present invention and are used together with the invention to illustrate the principles of the invention.

[0033] As attached Figure 1 As shown, the present invention provides a rapid fuel injection step-by-step device for use in aircraft engine surge testing, comprising a servo motor 1, a fuel injector 2, a first remote switching valve 5, and a first check valve 7. This system constructs a rapidly driven fuel injection step-by-step solution.

[0034] The fuel injector 2 can optionally employ one of the following: a single-rod piston hydraulic cylinder, a plunger hydraulic cylinder, a diaphragm positive displacement pump, or a screw positive displacement pump. All of these structures share a common feature: a servo motor 1 drives its moving parts, creating a closed volumetric cavity within it. During operation, this cavity cyclically increases and decreases, forcibly squeezing out fuel from the low-pressure fuel system, achieving step-high-pressure injection without external pressurization. Regardless of the structure used, the injection volume can be accurately calculated by monitoring the product of the displacement of the moving parts (such as piston rod displacement, plunger stroke, diaphragm deformation, and screw rotation) and structural parameters (such as cavity cross-sectional area and screw lead), thus achieving closed-loop control of the total injected fuel volume. Different structures are suitable for different application scenarios: the single-rod piston hydraulic cylinder has a simple structure and high rigidity, making it the optimal implementation; the plunger hydraulic cylinder is suitable for higher working pressure requirements; the diaphragm positive displacement pump can isolate fuel from mechanical parts, avoiding contamination; and the screw positive displacement pump can achieve low-pulsation, multi-cycle micro-injection, supporting complex pressure waveforms. Those skilled in the art can select the appropriate type of injector according to the experimental requirements, and all such selections fall within the scope of protection of this invention. The following description uses a single-rod piston hydraulic cylinder as an example of an injector 2.

[0035] To address the technical problems of system complexity, high cost, and slow response speed of existing technologies using a combination of high-pressure fuel pump stations and solenoid valves, this invention employs a servo motor 1 to drive the piston rod of the fuel injector 2, forming a high-pressure fuel generation and execution unit. On one hand, it eliminates redundant components such as high-pressure fuel pump stations, accumulators, high-pressure pipelines, and solenoid valves, significantly simplifying the system structure and reducing manufacturing costs and installation space requirements. On the other hand, the servo motor has millisecond-level dynamic response capability, directly and without delay controlling the displacement and speed of the piston rod, avoiding the opening delay of traditional solenoid valves, pipeline inertia delay, and pressure fluctuation attenuation. This achieves step-like instantaneous fuel injection (response time ≤ 5ms), meeting the stringent requirements of dynamic response speed and injection accuracy for the breath-force test of next-generation aero-engines.

[0036] Furthermore, the servo motor 1 is driven and connected to the piston rod of the injector 2 via a helical pair 4. Preferably, the helical pair 4 can be a combination of a reducer and a ball screw, or a worm gear mechanism. When a reducer and a ball screw are used, their high transmission efficiency and low backlash characteristics enable the angular displacement of the servo motor 1 to be precisely and linearly converted into the linear displacement of the piston rod. Combined with the high-precision displacement sensor 11, closed-loop metering of the oil discharge volume in the rodless chamber (i.e., the volume chamber) of the injector 2 can be achieved, with an injection volume control accuracy better than ±1%. When a worm gear mechanism is used, its self-locking characteristic can effectively prevent the piston rod from retracting under fuel pressure at the moment the servo motor 1 is powered off or stopped, ensuring the stability of the injected fuel volume. This is particularly suitable for breath-forced tests that require multiple consecutive step injections. Those skilled in the art will understand that the above two structures are only preferred solutions for achieving precise linear motion transmission between the servo motor and the piston rod. Other direct drive methods, such as linear motors and hydraulic servo cylinders, can also achieve the purpose of this invention and should all fall within the scope of protection of this invention.

[0037] Furthermore, to address the issues in existing technologies where fuel step injection and normal engine operation share fuel lines, causing mutual interference and preventing continuous multiple injections, the rodless chamber of the injector 2 is divided into two branches via pipelines: the first branch is the suction circuit, connected to the low-pressure fuel supply system (which can come from a fuel depot or low-pressure fuel pump station, and is clean fuel free of air) via the second remote switching valve 10; the second branch is the injection circuit, sequentially connected to the first pressure sensor 3, the first remote switching valve 5, the first check valve 7, and the second pressure sensor 6, ultimately connecting to the engine fuel main. This invention establishes independent suction and injection circuits, and isolates the injection system from the engine fuel main via the first check valve 7. The first check valve 7 isolates the injection system's pipeline from the engine fuel main during non-injection periods, ensuring uninterrupted normal fuel supply to the engine; during injection, high-pressure fuel opens the first check valve 7 and injects into the engine fuel main without flowing back into the system. Meanwhile, by switching the second remote switching valve 10, the fuel injector 2 can draw fuel from the low-pressure fuel system again after completing one fuel injection, in preparation for the next fuel injection, thereby realizing continuous step injection of fuel multiple times.

[0038] Furthermore, to address the issue of high-pressure fuel potentially flowing back into the engine fuel control unit and damaging its precision components, a bypass branch is installed in the pipeline between the first one-way valve 7 and the engine fuel main. A second one-way valve 8 is installed on this bypass branch, and its outlet is connected to the engine fuel control unit. When high-pressure fuel is injected into the fuel main, it may flow back into the engine fuel control unit, potentially damaging this precision component. This invention provides a second one-way valve 8 between the engine fuel control unit and the fuel main, with the forward direction allowing fuel to flow from the engine fuel control unit to the fuel main. When the system performs a step-injection of fuel, the high-pressure fuel generated by the injector 2 enters the fuel main. This high pressure acts on the outlet of the second one-way valve 8, causing it to close tightly, thus reliably preventing high-pressure fuel from flowing back into the engine fuel control unit and protecting this expensive and precision component.

[0039] Furthermore, to address the technical problem of existing systems lacking an effective overpressure protection mechanism and posing safety hazards, a safety valve 9 is installed between the outlet of the first pressure sensor 3 and the inlet of the first remote switching valve 5 on the aforementioned second branch for overpressure protection. The safety valve 9 has a preset pressure threshold; when the pressure in the pipeline exceeds the safety valve's set threshold, fuel will overflow from the safety valve 9. For accurate measurement, a measuring cup or other collection device can be placed at the outlet of the safety valve 9. This invention solves the technical problem of the system lacking an effective overpressure protection mechanism by providing physical overpressure protection through the safety valve 9; the safety valve 9 provides the system with a final physical defense. When the control system fails or abnormal blockage occurs in the pipeline, causing a sudden pressure rise exceeding the threshold, the safety valve 9 automatically opens to release pressure, preventing damage to critical equipment such as the engine fuel main and sensors due to overpressure.

[0040] Furthermore, to address the technical problem of low fuel injection control accuracy in existing technologies, a high-precision displacement sensor 11 is installed on the fuel injector 2 to monitor the piston rod displacement in real time. A first pressure sensor 3 monitors the fuel pressure at the fuel injector 2 outlet, while a second pressure sensor 6 monitors changes in fuel pressure within the engine's fuel main. Existing technologies control fuel injection volume in an open-loop manner using the solenoid valve's opening time, resulting in low accuracy and a lack of effective overpressure protection mechanisms, posing safety hazards. This invention constructs a closed-loop, precise metering and monitoring system by incorporating the displacement sensor 11, the first pressure sensor 3, the second pressure sensor 6, and a collection device at the outlet of the safety valve 9. Specifically, by monitoring the piston displacement through the high-precision displacement sensor 11, the theoretical fuel volume (area × displacement) discharged from the rodless chamber of the injector 2 can be accurately calculated, achieving precise control of the fuel injection process. Combined with the pressure changes monitored by the first pressure sensor 3, the control strategy can be further optimized. After the fuel injection is completed, by measuring the amount of overflow collected at the outlet of the safety valve 9, the difference between the theoretical fuel discharge and the safety valve overflow can be obtained. This difference is the actual amount of fuel precisely injected into the engine. This closed-loop metering method fundamentally solves the problem of poor accuracy in open-loop control, that is, it solves the technical problem of low fuel injection control accuracy in the prior art.

[0041] The fuel step rapid injection method of the present invention includes: Step S1: Under normal operating conditions, the fuel injection circuit of the fuel step injection device is physically isolated from the engine fuel main.

[0042] During normal engine operation, the first remote switch valve 5 is closed, which physically disconnects the fuel injection circuit of the fuel step injection device from the engine fuel main. The pressurized fuel output by the engine fuel control device flows into the engine fuel main through the second one-way valve 8, providing a stable fuel supply to the engine. The injection system does not interfere with the engine control circuit.

[0043] Step S2: After the injector 2's volume chamber is filled with oil, the passage between the injector and the low-pressure fuel source is cut off.

[0044] When a step injection of fuel is required, the second remote switch valve 10 is opened to connect the rodless chamber of the injector 2 with the low-pressure fuel supply system; the servo motor 1 is controlled to rotate in the forward direction, driving the piston rod of the injector 2 to extend outward through the screw pair 4, thereby increasing the volume of the rodless chamber, creating a negative pressure, and drawing in low-pressure fuel; when the rodless chamber is full of fuel, the second remote switch valve 10 is closed to cut off the passage between the injector and the low-pressure fuel source, making the fuel in the rodless chamber sealed, and completing the preparation for fuel intake.

[0045] Step S3: Open the first remote switching valve 5, and the servo motor 1 drives the fuel injector 2 to achieve high-pressure fuel injection and step triggering.

[0046] The first remote switching valve 5 is opened, connecting the rodless chamber of the injector 2 to the engine fuel main; the servo motor 1 is controlled to rotate in the opposite direction at high speed, driving the piston rod to retract rapidly at a preset acceleration through the screw pair 4, causing the volume of the rodless chamber to decrease sharply, applying high pressure to the fuel in the chamber; when the fuel pressure in the chamber exceeds the pressure of the engine fuel main, the first one-way valve 7 is opened, and fuel is injected into the main in a step manner; during the injection process, the first pressure sensor 3 collects the injector outlet pressure signal in real time, and when the pressure rise rate is detected to be greater than a preset threshold, the injection completion flag is triggered; the second pressure sensor 6 synchronously collects the fuel main pressure change to determine the compressor operating point response.

[0047] Step S4: The injection volume is precisely executed by controlling the displacement of the piston rod of the oil injector 2.

[0048] During the injection process in step S3, the displacement sensor 11 collects the displacement signal of the piston rod of the injector 2 in real time and feeds the signal back to the controller of the servo motor 1. The controller calculates the displacement distance that the piston rod should retract according to the preset target injection amount. When the actual displacement value fed back by the displacement sensor 11 reaches the preset target value, the servo motor 1 is immediately controlled to stop running and the injection action is cut off, thereby realizing the precise control of the fuel injection amount based on displacement in a closed loop, with an injection amount error of ≤±1%.

[0049] Step S5: After injection is complete, the system is reset and returns to step S2 to achieve continuous injection.

[0050] After injection is completed, the first remote switch valve 5 is closed to disconnect the injector from the engine fuel main. If the next injection is required, the system automatically returns to step S2 and repeats the fuel suction and injection cycle to achieve continuous, delay-free, and highly repeatable fuel step injection, which meets the requirements of multi-cycle breathing test of aero-engines.

[0051] In step S3, if the pressure in the pipeline between the injector 2 outlet and the first check valve 7 exceeds the set threshold of the safety valve 9 due to any reason (such as the accidental closure of the first remote switching valve 5, pipeline blockage, etc.), the safety valve 9 will automatically open to release pressure, and some fuel will overflow from the outlet and be collected by the collection device. This action protects the safety of downstream equipment such as the engine fuel main and provides data for accurate measurement. The total amount of fuel injected in this step injection is ultimately obtained accurately in the following way: the theoretical fuel displacement is calculated based on the piston displacement and rodless chamber cross-sectional area recorded by the displacement sensor 11; then the overflow amount collected by the collection device at the outlet of the safety valve 9 is subtracted, and the difference is the actual amount of fuel injected into the engine.

[0052] In summary, this invention solves the problems of complexity, high cost, and slow response in existing systems through the direct drive structure of the servo motor 1 and the fuel injector 2; it addresses the compatibility, safety, and protection issues between the system and the engine's original fuel system through the layout of the first one-way valve 7, the second one-way valve 8, and the safety valve 9; and it solves the technical challenge of precise fuel injection control through the combination of the displacement sensor 11 and the outlet collection device of the safety valve 9. Overall, this system achieves the advantages of simple structure, low cost, fast injection speed, precise and controllable fuel injection volume, continuous multiple injection capability, and high safety, fully meeting the stringent requirements of the next-generation aero-engine surge test for a step-injection fuel system.

Claims

1. A fuel injection step-rapid injection device, characterized in that, include: Servo motor (1), oiler (2), first remote switching valve (5) and first check valve (7); The oil injector (2) has a variable volume chamber; The servo motor (1) is used to drive the volume chamber of the oil injector (2) to change cyclically between increasing and decreasing; The volume chamber is connected in sequence to the first remote switching valve (5) and the first one-way valve (7) through pipelines, and finally connected to the engine fuel main pipe; When a step-fast fuel injection is performed, the servo motor (1) drives the volume chamber to decrease rapidly, so that the fuel in the volume chamber is pressurized and injected into the engine fuel manifold through the first remote switching valve (5) and the first one-way valve (7), thereby realizing a step-fast fuel injection.

2. The fuel injection step-rapid injection device according to claim 1, characterized in that, The oil injector (2) adopts a single-rod piston hydraulic cylinder, and its rodless chamber is the volume chamber.

3. The fuel injection step-rapid injection device according to claim 1, characterized in that, The oil injector (2) is a plunger-type hydraulic cylinder, and its cavity is the volume chamber.

4. The fuel injection step-rapid injection device according to claim 1, characterized in that, It also includes a second pressure sensor (6), which is installed on the pipeline between the first check valve (7) and the engine fuel manifold, for monitoring changes in fuel pressure entering the engine fuel manifold.

5. The fuel injection step-fast injection device according to claim 1, characterized in that, The servo motor drives the volume chamber of the oiler (2) to change through the screw pair (4).

6. The fuel injection step-fast device according to claim 5, characterized in that, The helical pair (4) adopts a combination of a reducer and a ball screw mechanism.

7. The fuel injection step-fast device according to claim 5, characterized in that, The helical pair (4) adopts a worm gear mechanism.

8. The fuel injection step-rapid injection device according to claim 1, characterized in that, A bypass passage is provided between the first one-way valve (7) and the engine fuel main pipe. A second one-way valve (8) is provided on the bypass passage. The second one-way valve (8) is connected to the engine fuel control device. When the engine is working normally, the pressurized fuel of the engine fuel control device flows into the engine fuel main pipe automatically through the second one-way valve (8).

9. The fuel injection step-fast device according to claim 2, characterized in that, The injector (2) is equipped with a displacement sensor (11) to monitor the displacement of its piston rod. By monitoring the displacement change of the injector piston rod, the output fuel quantity of the rodless chamber of the injector can be accurately calculated.

10. A method for rapid step injection of fuel, characterized in that, Fuel step injection is performed using the fuel step injection device according to any one of claims 1-9.

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