A test method suitable for rotor engine vibration noise optimization of low altitude aircraft
By optimizing the vibration and noise performance of the rotor engine of low-altitude aircraft through a systematic testing method, the problems of poor sealing and large energy loss were solved, and NVH testing and optimization in multiple environments were realized, thereby improving the reliability and early warning capability of the engine.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HARBIN DONGAN AUTOMOTIVE ENGINE MFG CO LTD
- Filing Date
- 2026-05-08
- Publication Date
- 2026-07-28
AI Technical Summary
Low-altitude aircraft rotor engines face problems such as poor sealing, large energy loss, and gas leakage under high load operation, which leads to high-frequency noise such as combustion excitation degradation and airflow leakage. There is a lack of effective vibration and noise testing methods to optimize performance and provide early warning of abnormal operation.
A testing method is provided, including confirming the structural information of the rotary engine, analyzing the relevant operating conditions for NVH performance, formulating a test project plan, installing vibration and acoustic equipment, conducting iterative tests, analyzing the noise contribution, and formulating an optimization scheme until the NVH performance target is met.
It enables NVH vibration and noise testing in individual units, powertrains, and real-world application environments, optimizes rotary engine performance, improves reliability, and provides early warning of abnormal operation.
Smart Images
Figure CN122468433A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of NVH testing technology, and in particular relates to a testing method suitable for optimizing the vibration and noise of rotor engines in low-altitude aircraft. Background Technology
[0002] The rapid development of the low-altitude economy has placed higher demands on green and efficient aviation power. Therefore, actively cultivating and expanding emerging future industries such as the low-altitude economy, strengthening the tackling of key core technologies, accelerating the innovative application of green aviation equipment, and promoting the healthy development of the low-altitude economy require the development of efficient engines such as hybrid power and hydrogen fuel cells to become key development directions.
[0003] The rotary engine is a compact internal combustion engine with a high power-to-weight ratio, widely used in aerospace, automotive engineering, and miniaturized power units. Compared to traditional reciprocating piston engines, the rotary engine's operation is relatively simple, primarily using the rotation of a rotor within the cylinder to complete the intake, compression, combustion, and exhaust processes. Due to its high power-to-weight ratio, small size, and lightweight nature, the triangular rotary engine is widely used in equipment such as unmanned aerial vehicles (UAVs).
[0004] However, rotary engines also face technical challenges in practical applications, such as poor sealing, significant energy loss, and gas leakage. These problems are particularly pronounced under high-load operation, leading to deteriorated combustion excitation and high-frequency noise caused by airflow leakage. Therefore, there is an urgent need for an effective vibration and noise testing method to support the optimization of vibration and noise performance levels, while also providing early warning of abnormal operating conditions and improving engine reliability. Summary of the Invention
[0005] The purpose of this invention is to provide a test method for optimizing the vibration and noise of a rotor engine in a low-altitude aircraft, providing support for optimizing vibration and noise performance levels, and providing early warning of abnormal operating conditions to improve engine reliability.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a test method for optimizing the vibration and noise of a rotor engine in a low-altitude aircraft, the test method comprising the following steps:
[0007] Step S1: Confirm the relevant structural information of the target rotary engine under test and calculate the key NVH performance parameters;
[0008] Step S2: Confirm the working principle and operating condition information of the rotary engine, and analyze the operating conditions related to NVH performance;
[0009] Step S3: Based on the collected information, develop an NVH test project plan map;
[0010] Step S4: Install the prototype, set up vibration and acoustic acquisition equipment, and iterate the test plan based on the actual test results;
[0011] Step S5: Based on the test data, analyze the acoustic contribution of combustion order, rotor, eccentric shaft and gear order, analyze the reasons in combination with their characteristics, and formulate optimization schemes;
[0012] Step S6: Implement the optimization plan and create optimized prototypes for verification and iteration;
[0013] Step S7: Based on the product positioning requirements, repeat steps S4, S5, and S6 until the rotary engine NVH performance meets the target.
[0014] Furthermore, in step S1, the specific main structure of the rotary engine is analyzed, the rotary engine speed relative to the output end and the speed ratio of the planetary mechanism are calculated, and the planetary mechanism, eccentric shaft, rotor and combustion power order are confirmed.
[0015] Furthermore, in step S2, when analyzing the operating conditions related to NVH performance, the mechanical layout structure is confirmed, the engine working stroke is confirmed, and the phase relationship of each cylinder is confirmed.
[0016] Furthermore, in step S3, based on the information collected in steps S1 and S2, such as the rotor mechanical structure, the phase relationship between the eccentric shaft and the balance redistribution, the inherent modal properties of the sealing structure, the combustion phase relationship of the working chamber, and the rated speed and power, an NVH test project plan map is formulated.
[0017] Furthermore, step S4 involves conducting NVH vibration and noise tests on the rotor engine of a low-altitude aircraft under the conditions of a single-unit performance test bench, a powertrain test bench, a semi-anechoic chamber environment, and the actual application environment of the product, according to the testing requirements. A sound acquisition device is set up at a certain distance from the mechanical oil pump, and A-weighted sound pressure level or sound power is used for acquisition. The test plan is then iterated and corrected based on the test results.
[0018] Furthermore, in step S5, when analyzing the main noise contribution frequencies based on the test data, analyzing the causes in conjunction with their characteristics, and formulating optimization schemes, the transient and steady-state test data are analyzed. For the transient conditions, the analysis is performed through acoustic diagnosis, difference method, masking effect, sound-to-noise ratio, and pure-tone-to-noise ratio evaluation. For the steady-state conditions, characteristic frequency filtering is performed, and the analysis is performed through envelope analysis, Hilbert transform, and fast Fourier transform.
[0019] Furthermore, step S6 involves combining simulation model calculation results and industry experience to comprehensively consider the implementation cost and verification cycle of the optimization scheme.
[0020] Furthermore, step S7 involves repeating steps S4, S5, and S6 according to product positioning requirements until the NVH performance of the rotary engine meets the target.
[0021] Compared with the prior art, the beneficial effects of the present invention are:
[0022] 1. The present invention provides a test method for vibration and noise optimization of rotor engines for low-altitude aircraft. This method can perform NVH vibration and noise tests on rotor engines for low-altitude aircraft under the conditions of individual performance test benches, powertrain test benches, and actual application environments, providing key technical support for vibration and noise optimization of rotor engines for low-altitude aircraft. Attached Figure Description
[0023] Figure 1 This is a flowchart illustrating the present invention. Detailed Implementation
[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0025] The purpose of this invention is to provide a testing method suitable for the vibration and noise optimization of low-altitude aircraft rotor engines. This method can perform NVH vibration and noise tests on low-altitude aircraft rotor engines under individual performance test benches, powertrain test benches, and actual product mounting conditions, providing key technical support for the vibration and noise optimization of low-altitude aircraft rotor engines.
[0026] To achieve the above objectives, the present invention provides a testing method suitable for optimizing the vibration and noise of a rotor engine in a low-altitude aircraft, comprising:
[0027] Step S1: Confirm the relevant structural information of the target rotary engine under test and calculate the key NVH performance parameters;
[0028] Step S2: Confirm the working principle and operating condition information of the rotary engine, and analyze the operating conditions related to NVH performance;
[0029] Step S3: Based on the collected information, develop an NVH test project plan map;
[0030] Step S4: Install the prototype, set up vibration and acoustic acquisition equipment, and iterate the test plan based on the actual test results;
[0031] Step S5: Based on the test data, analyze the acoustic contribution of combustion order, rotor, eccentric shaft and gear order, analyze the reasons in combination with their characteristics, and formulate optimization schemes.
[0032] Step S6: Implement the optimization plan and create optimized samples for verification and iteration;
[0033] Step S7: Based on product positioning requirements, repeat steps S4, S5, and S6 until the rotary engine's NVH performance meets the target.
[0034] Specifically, in step S1, when confirming the relevant structural information of the rotary engine, the main structure of the rotary engine, namely the planetary gear mechanism composed of internal and external gears and eccentric shaft, is analyzed to calculate the rotary engine's rotational frequency relative to the output end, the speed ratio of the planetary mechanism, and to confirm the planetary mechanism, eccentric shaft, rotor, and combustion order.
[0035] In this embodiment, during operation, the external gear ring, i.e., the rotor speed W r Eccentric shaft speed W, external gear speed W k The number of teeth on the external gear ring Z r The number of teeth on the external gear Z k The external gear is fixed on a rigid body, and the ratio of the number of teeth on the external gear ring to the number of teeth on the external gear is Z. r Z k =3:2, therefore:
[0036]
[0037] The eccentric shaft rotates at three times the rotor speed, meaning that for every one revolution of the rotor, the engine performs three work operations while the eccentric shaft rotates three times. Calculate the relative output frequency, the balance shaft's operating order R=1, the rotor's operating order Rr=1 / 3, and the planetary gear meshing order Rz=Z. r ×Rr, combustion operating order Re=1, and harmonic frequencies iR, iRr, iRz, iRe for each operating order, where i=1,2,3,...,n, and n is the harmonic frequency multiple. In this embodiment, n=6 is selected, that is, focusing on the first 6 harmonic frequencies can meet the NVH performance optimization evaluation requirements.
[0038] Specifically, in step S2, when confirming the working principle, structural layout, and operating condition information of the rotary engine, and analyzing the operating conditions related to NVH performance, the mechanical layout structure, the engine working stroke, and the phase relationship of each cylinder are confirmed.
[0039] In this embodiment, the main mechanism of the triangular rotor engine is a planetary mechanism composed of a pair of internal and external gears and an eccentric shaft. For one cylinder, the eccentric shaft completes one working cycle on average with one revolution. The working process of the rotor engine is divided into four processes: intake, compression, power, and exhaust. The corresponding eccentric angles α1, α2, and α3 of the three working chambers are: α2 = α1 + 360°, α3 = α1 + 720°. Based on the ignition phase and pressure fluctuations in the working chambers, the intake and exhaust pulsation order is verified, the resonant frequency of the top seal and side seal ring modes and the high-frequency pulse frequency of the flow field are confirmed, the dynamic balance matching of the front and rear eccentric counterweights and the torsional vibration of the engine are verified, etc.
[0040] Specifically, in step S3, when planning the NVH test project, an NVH test project plan map is formulated based on the information collected in steps S1 and S2, such as the rotor mechanical structure, the phase relationship between the eccentric shaft and the balance redistribution, the inherent modal properties of the sealing structure, the combustion phase relationship of the working chamber, and the rated speed and power.
[0041] In this embodiment, tests were conducted under the following conditions: mechanical reverse drag, no load, 25% load, 50% load, 75% load, and 100% load; idling to rated speed; idling to the maximum speed range; gradual acceleration / deceleration at a rate of 50 rpm / s; and rapid acceleration / deceleration at a rate of 500 rpm / s. The tests also included steady-state tests at idle speed, steady-state tests at rated speed, and steady-state tests at speeds near commonly used target power generation conditions. The performance tuning schemes were compared and tested to evaluate NVH performance indicators, assess the presence of vibration and noise islands, and comprehensively select the power generation speed under each power requirement.
[0042] Specifically, in step S4, when mounting the prototype, setting up acoustic acquisition equipment, and conducting tests according to the plan and on-site test results, the NVH vibration and noise test of the low-altitude aircraft rotor engine is carried out under the conditions of mounting in a single performance test bench, powertrain test bench, semi-anechoic chamber environment, and actual product application environment, according to the test requirements. A sound acquisition device is set up at a certain distance from the mechanical oil pump, and A-weighted sound pressure level or sound power is used for acquisition. The test plan is iterated and corrected by combining the test results feedback, so as to achieve comprehensive, accurate and efficient data test acquisition.
[0043] In this embodiment, in the environments of the single-unit performance test bench and the powertrain test bench, the monitoring and data acquisition are mainly based on the three-dimensional vibration sensor, supplemented by the near-field noise acquisition at 20cm in key locations; in the semi-anechoic chamber environment, the data acquisition is mainly based on the 4-point method, the 8-point method, the 1-meter noise, the near-field noise at 20cm in key locations, and the three-dimensional vibration sensor; in the actual product installation state, the data acquisition is mainly based on the noise in the driver's right ear, the near-field noise at 20cm in the rotor engine, and the three-dimensional vibration sensor data acquisition of key transmission paths such as the active and passive suspension.
[0044] Specifically, in step S5, when analyzing the main noise contribution frequencies based on test data, analyzing the causes in conjunction with their characteristics, and formulating optimization schemes, the test data for transient and steady-state conditions are analyzed. For transient conditions, methods such as acoustic diagnosis, difference method, masking effect, sound-to-noise ratio, and pure-tone-to-noise ratio evaluation are used for analysis. For steady-state conditions, characteristic frequency filtering is performed, and methods such as envelope analysis, Hilbert transform, and fast Fourier transform are used for analysis.
[0045] In this embodiment, the following parameters are evaluated relative to the output frequency fo: balance shaft operating order R=1, rotor operating order Rr=1 / 3, planetary gear meshing order Rz=Zr×Rr, combustion operating order Re=1, and harmonic harmonics iR, iRr, iRz, iRe for each operating order, where i=1,2,3,...,n, and n is the harmonic harmonic multiple. In this embodiment, n=6 is selected, i.e., the first 6 harmonics are considered. The decoupling effect of resonance bands, impact bands, etc., with the inherent modes of each component is considered, as well as the high-frequency pulsation frequency of the flow field caused by top and side seal leakage.
[0046] Specifically, in step S6, when implementing the optimization scheme and making verification samples, the implementation cost and verification cycle of the optimization scheme should be comprehensively considered in conjunction with the simulation model calculation results, industry experience, etc.
[0047] In this embodiment, to address the problem of locked NVH post-processing analysis of test data, optimization is carried out from the source and path aspects. This is achieved by adjusting combustion control parameters, optimizing the front and rear balance weight arrangement, modifying planetary gear parameters, and optimizing the sealing ring structure and materials, thereby improving the NVH performance of the rotary engine.
[0048] Specifically, in step S7, steps S4, S5, and S6 are repeated according to product positioning requirements until the NVH performance of the rotary engine meets the target. This process fully demonstrates the product positioning needs, comprehensively considers factors such as cost and timeline, adjusts reasonable NVH performance indicators, and finds the optimal improvement solution that balances effect, cost, and timeline through testing and analysis. In this embodiment, precise measurement of rotor dynamic balance, simulation optimization of the balancing weight scheme, combustion performance calibration optimization, and turbulence suppression through intake and exhaust flow field simulation optimization are performed to achieve NVH performance improvement under controllable cost and timeline.
[0049] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.
[0050] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A test method for optimizing the vibration and noise of a rotor engine in a low-altitude aircraft, characterized in that: The testing method includes the following steps: Step S1: Confirm the relevant structural information of the target rotary engine under test and calculate the key NVH performance parameters; Step S2: Confirm the working principle and operating condition information of the rotary engine, and analyze the operating conditions related to NVH performance; Step S3: Based on the collected information, develop an NVH test project plan map; Step S4: Install the prototype, set up vibration and acoustic acquisition equipment, and iterate the test plan based on the actual test results; Step S5: Based on the test data, analyze the acoustic contribution of combustion order, rotor, eccentric shaft and gear order, analyze the reasons in combination with their characteristics, and formulate optimization plan; Step S6: Implement the optimization plan and create optimized prototypes for verification and iteration; Step S7: Based on the product positioning requirements, repeat steps S4, S5, and S6 until the NVH performance of the rotary engine meets the target.
2. The test method for optimizing vibration and noise of a rotor engine in a low-altitude aircraft according to claim 1, characterized in that: In step S1, the specific main structure of the rotary engine is analyzed, the rotational frequency of the rotary engine relative to the output end and the speed ratio of the planetary mechanism are calculated, and the planetary mechanism, eccentric shaft, rotor and combustion power order are confirmed.
3. The test method for optimizing vibration and noise of a rotor engine in a low-altitude aircraft according to claim 2, characterized in that: In step S2, when analyzing the operating conditions related to NVH performance, the mechanical layout structure is confirmed, the engine working stroke is confirmed, and the phase relationship of each cylinder is confirmed.
4. The test method for optimizing vibration and noise of a rotor engine in a low-altitude aircraft according to claim 3, characterized in that: In step S3, based on the information collected in steps S1 and S2, such as the rotor mechanical structure, the phase relationship between the eccentric shaft and the balance redistribution, the inherent modal properties of the sealing structure, the combustion phase relationship of the working chamber, and the rated speed and power, an NVH test project plan map is formulated.
5. The test method for optimizing vibration and noise of a rotor engine in a low-altitude aircraft according to claim 4, characterized in that: Step S4 involves conducting NVH vibration and noise tests on the rotor engine of a low-altitude aircraft under the conditions of a single performance test bench, a powertrain test bench, a semi-anechoic chamber environment, and the actual application environment of the product, according to the testing requirements. A sound acquisition device is set up at a certain distance from the mechanical oil pump, and A-weighted sound pressure level or sound power is used for acquisition. The test plan is then iterated and corrected based on the test results.
6. The test method for optimizing vibration and noise of a rotor engine in a low-altitude aircraft according to claim 5, characterized in that: In step S5, based on the test data, the main noise contribution frequencies are analyzed, and the causes are analyzed in combination with their characteristics. When formulating an optimization plan, the test data for transient and steady-state conditions are analyzed. For transient conditions, the analysis is carried out through acoustic diagnosis, difference method, masking effect, sound-to-noise ratio, and pure-tone-to-noise ratio. For steady-state conditions, characteristic frequency filtering is performed, and the analysis is carried out through envelope analysis, Hilbert transform, and fast Fourier transform.
7. The test method for optimizing vibration and noise of a rotor engine in a low-altitude aircraft according to claim 6, characterized in that: Step S6 involves combining simulation model calculation results and industry experience to comprehensively consider the implementation cost and verification cycle of the optimization scheme.
8. A test method for optimizing vibration and noise of a rotor engine in a low-altitude aircraft according to claim 7, characterized in that: Step S7 involves repeating steps S4, S5, and S6 according to product positioning requirements until the NVH performance of the rotary engine meets the target.