A method, system and storage medium for accelerating coarse-fidelity optimization

Abstract

The application discloses an accelerating rough sound optimization method and system and a storage medium, which comprises the following steps: step one, arranging cylinder pressure, torsional vibration, vibration sensor and microphone on a whole vehicle; step two, the whole vehicle drives according to a set working condition, and first test data is collected; step three, the whole vehicle drives according to a problem working condition, and second test data is collected; step four, the second test data is analyzed to determine an excitation source of the accelerating rough sound in the vehicle; step five, a whole vehicle model is established by using an Operational Transfer Path Analysis module of LMS software, the first test data is imported into the whole vehicle model, and initial transfer functions on each transfer path are calculated; step six, the initial transfer functions and the second test data are imported into the whole vehicle model, and the main transfer path with the largest contribution to the noise in the vehicle under the problem working condition is calculated; and step seven, the excitation source and structural members on the main transfer path are optimized. The accelerating rough sound in the vehicle can be optimized from the excitation source and the transfer path, and the comfort is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of vehicle NVH technology, specifically to accelerated roughness noise optimization methods, systems, and storage media. Background Technology

[0002] As cars become increasingly common in people's lives, the demand for automotive comfort is rising. A slight, rough noise during acceleration in some automatic gasoline engine models has drawn attention and complaints. This so-called rough acceleration noise is generated by the 0.5-order combustion excitation modulation at the engine's source. Subjectively, it feels like a noticeable graininess, a "coughing" sound, and the noise is discontinuous. This is especially common in vehicles equipped with automatic transmissions (AT), where the transmission is not locked when the noise occurs, making sound optimization more challenging. Summary of the Invention

[0003] The purpose of this invention is to provide an acceleration roughness sound optimization method, system, and storage medium that can optimize in-vehicle acceleration roughness sound from both the excitation source and the transmission path, thereby improving comfort.

[0004] The accelerated roughness sound optimization method of the present invention includes the following steps:

[0005] Step 1: Install cylinder pressure and torsional vibration sensors on the engine body, install vibration sensors on engine wheel system accessories and other locations of interest throughout the vehicle, and install microphones at the driver's right ear and near the engine.

[0006] Step two: The vehicle is driven under the set operating conditions, and the first test data from the vibration sensor and microphone is collected;

[0007] Step 3: Drive the vehicle under the problematic operating conditions and collect second test data from the vibration sensor and microphone;

[0008] Step four: Perform spectrum analysis, wavelet analysis and modulation analysis on the second test data to determine the excitation source of the acceleration rough sound inside the vehicle, and analyze the key components at the engine source that contribute to the acceleration rough sound.

[0009] Step 5: Use the Operational Transfer Path Analysis module of LMS software to build a vehicle model, import the first test data into the vehicle model, and calculate the initial transfer function on each transfer path.

[0010] Step 6: Import the initial transfer function and the second test data into the vehicle model and calculate the main transmission path that contributes the most to the in-vehicle noise under the problem condition.

[0011] Step 7: Optimize the materials and structure of the excitation source and structural components along the main transmission path to reduce the rough acceleration noise inside the vehicle, thereby achieving the goal of avoiding the frequency of critical components at the source and reducing the energy of the complaining frequency along the entire vehicle path.

[0012] Furthermore, the vehicle-wide focus areas in step one include the suspension mounts and suspension brackets.

[0013] Furthermore, the structural optimization in step seven specifically involves: using local structural reinforcement or dynamic vibration absorbers to attenuate the energy in the problem frequency range for the structural components on the excitation source and main transmission path, in order to reduce the transmission of accelerated rough sound energy.

[0014] Furthermore, the setting condition in step two is a second-gear constant throttle slow acceleration condition; the problem condition in step three is a start-up acceleration condition.

[0015] An accelerated rough sound optimization system includes: a sensor module comprising cylinder pressure and torsional vibration sensors mounted on the engine body, vibration sensors located near the engine wheel system and at other points of interest in the vehicle, and microphones located at the driver's right ear and near the engine; the sensor module is connected to a data acquisition module; the data acquisition module is used to collect test data from the vibration sensors and microphones during vehicle operation; a vehicle model building module, specifically the Operational Transfer Path Analysis module of the LMS software, is used to build a vehicle model; and an analysis and calculation module performs spectral analysis, wavelet analysis, and modulation analysis on the cylinder pressure, torsional vibration, vibration, and noise data from the second test data to clarify the generation mechanism of the rough sound source, analyze the key components contributing to the engine source, import the first test data into the vehicle model, calculate the initial transfer function on each transmission path, import the initial transfer function and the second test data into the vehicle model, and calculate the main transmission path that contributes the most to the in-vehicle noise under the problem condition.

[0016] In terms of optimization modules, this invention advocates reducing source excitation by adopting frequency avoidance and increasing crankshaft stiffness in engine source gear train accessories, changing belt material and motor housing material to avoid rough sound frequencies, and advocating replacing ductile iron crankshaft with forged steel crankshaft to reduce source torsional vibration excitation by increasing crankshaft stiffness; in terms of vehicle path, reducing the transmission of rough sound energy by strengthening the body structure at the suspension connection, etc.

[0017] A storage medium storing a computer-readable program, which, when invoked, performs the steps of the method for accelerating coarse sound optimization as described in this invention.

[0018] This invention first drives the vehicle under set operating conditions, collecting first test data from vibration sensors and microphones; then drives the vehicle under problematic operating conditions, collecting second test data from vibration sensors and microphones. Next, the OTPA method is used to efficiently identify the main transmission path contributing the most to in-vehicle noise under the problematic operating conditions. Targeted structural optimization is then performed on the excitation source and structural components along the main transmission path. Frequency avoidance effectively reduces rough acceleration noise inside the vehicle. The final evaluation method proposes an in-vehicle roughness of no more than 0.09 asper, effectively improving passenger comfort. Attached Figure Description

[0019] Figure 1 This is a schematic diagram showing the arrangement of vibration sensors on the engine body;

[0020] Figure 2 This is a schematic diagram of the arrangement of vibration sensors on the gear train accessories;

[0021] Figure 3 This is a schematic diagram of the microphone arrangement;

[0022] Figure 4 These are the spectrum diagrams of each measuring point;

[0023] Figure 5 This is a schematic diagram of accelerated coarse sound modulation;

[0024] Figure 6 This is a wavelet analysis diagram of the engine signal;

[0025] Figure 7 This is a modal frequency analysis diagram of the engine and its accessories;

[0026] Figure 8 This is one of the schematic diagrams for OTPA transmission path analysis;

[0027] Figure 9 This is the second schematic diagram of the OTPA transmission path analysis.

[0028] In the diagram, 1—engine body, 2—mount bracket, 3—mount, 4—cylinder pressure sensor, 5—vibration sensor, 6—torsional vibration sensor, and 7—microphone. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0030] An accelerated method for optimizing rough sound includes the following steps:

[0031] Step 1, see Figure 1 and Figure 2 Vibration sensors 5 are installed on the wheel system accessories and other locations of interest throughout the vehicle on the engine block 1. Spark plug-type cylinder pressure sensors 4 are installed inside the cylinders of the engine block 1. Torsional vibration sensors 6 are also installed on the engine block 1. (See [link]) Figure 3 Microphones 7 are placed at the driver's right ear position and near the engine. The vehicle's points of interest include the suspension mount 3 and the suspension bracket 2, i.e., vibration sensors 5 are placed on both the suspension mount 3 and the suspension bracket 2.

[0032] Step two: Close the windows and air conditioning, fasten the driver's seatbelt to prevent warning sounds, and drive the vehicle under the set conditions. The set conditions are second gear constant throttle slow acceleration, under which the vehicle speed increases in increments of 5 km / s, and the first test data is collected from the vibration sensor and microphone.

[0033] Step 3: Close the windows and air conditioning, fasten the driver's seatbelt to prevent warning sounds, and drive the vehicle under the problem condition, which is the starting and acceleration condition. Collect the second test data from the vibration sensor and microphone.

[0034] Step four: Perform spectrum analysis on the second test data, see [link / reference]. Figure 4 Through filtered playback, the complaints about the harsh sound were mainly caused by the resonance band of 300-400Hz. Within this band, order groups spaced half an order apart appeared. These order groups interacted with each other, creating a grainy, harsh sound. This phenomenon is academically defined as modulation. (See [link to relevant documentation]). Figure 5 The acceleration roughness noise is modulated by a signal at the fundamental frequency of 16.5Hz, which is half the engine order. Noise data collected by microphones placed in the vehicle is used to calculate roughness using the Landes spec.Roughness sound quality calculation module. The roughness value in the 300~400Hz frequency band can characterize the severity of the acceleration roughness noise. Through scoring evaluation of different samples, a roughness of less than 0.9 asper is acceptable.

[0035] Wavelet analysis was performed by combining cylinder pressure and torsional vibration data; see [link / reference]. Figure 6 Under the excitation of the first cylinder's ignition, resonance occurs in multiple components including the crankshaft, alternator, compressor, and belt. The excitation from the first cylinder serves as the fundamental frequency, ranging from 15Hz to 17Hz. The crankshaft, compressor, alternator, and the belt-connected alternator and tensioner all exhibit modal frequencies within the 300-400Hz frequency band, forming a carrier wave. For the modal frequencies of various engine locations, please refer to [link to relevant documentation]. Figure 7From the modal frequency analysis of the engine and accessories, it can be seen that the excitation source of the rough acceleration sound in the vehicle is the engine. The crankshaft torsional vibration generates the excitation. The tensioner, generator, and compressor in the wheel system accessories respond significantly. The belt and motor are intermediate parts of the tensioner and compressor. Frequency avoidance of the belt and motor can decouple the resonance response of the wheel system accessories. Therefore, the crankshaft, belt, and motor are its key components.

[0036] Step five: The spectrum shows significant near-field radiated noise and 300-400Hz order groups in the suspension vibration, indicating both airborne and structural transmission possibilities. The OTPA method can more efficiently pinpoint the main transmission path and indicate the optimization direction. Specifically, a vehicle model is built using the Operational Transfer Path Analysis module of LMS software. The first test data is imported into the vehicle model, and the initial transfer function on each transmission path is calculated.

[0037] Step 6: Import the initial transfer function and the second test data into the vehicle model, and calculate the main transmission path that contributes the most to the in-vehicle noise under the problem condition. See [link / reference]. Figure 8 and Figure 9 It can be seen that the active Y-axis movement of the left and rear suspensions are the main contributors, while the contribution of air transmission is relatively small.

[0038] Step seven involves structurally reinforcing the excitation source and main transmission path components, or using dynamic vibration absorbers to attenuate the energy in the problem frequency range, thereby reducing the transmission of accelerated roughness sound energy. To suppress the response of the problem frequency band 300-400Hz in the vehicle interior noise roughness, this can be achieved by reducing the contribution from both the engine source excitation and the main transmission path. At the engine source, crankshaft stiffness is increased by replacing the spheroidal iron crankshaft with a steel one. Additionally, due to the coupling resonance phenomenon between the alternator, tensioner, and belt, a reinforced motor housing is used to avoid the modal frequencies in this range. Simultaneously, a polyester belt is used, and the frequency of the seventh belt segment is changed to effectively reduce resonance. On the main transmission path, dynamic vibration absorbers at corresponding frequencies are added to the left and rear suspensions to disperse the energy in the 300-400Hz range. Simultaneously, the downstream body strength is strengthened, such as at the suspension connection to the wheel hub. Combining these solutions, real-vehicle testing shows that the interior noise roughness in the 300-400Hz range is reduced from 0.1 asper to 0.08 asper.

[0039] An accelerated rough sound optimization system includes: a sensor module comprising vibration sensors arranged at engine wheel system attachments and other locations of interest on the vehicle, and microphones arranged at the driver's right ear and near the engine, the sensor module being connected to a data acquisition module; a data acquisition module for acquiring test data from the vibration sensors and microphones during vehicle operation; a vehicle model building module, specifically the Operational Transfer Path Analysis module of LMS software, for building a vehicle model using the Operational Transfer Path Analysis module of LMS software; and an analysis and calculation module for performing spectrum analysis, wavelet analysis, and modulation analysis on cylinder pressure, torsional vibration, vibration, and noise data from the second test data to clarify the generation mechanism of the rough sound source, analyze the key components contributing to the engine source, import the first test data into the vehicle model, and calculate the initial transfer function on each transmission path; import the initial transfer function and the second test data into the vehicle model to calculate the main transmission path contributing the most to the in-vehicle noise under the problem condition.

[0040] A storage medium storing a computer-readable program, which, when invoked, performs the steps of the method for accelerating coarse sound optimization as described in this invention.

[0041] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An accelerated roughness sound optimization method, characterized in that, Includes the following steps: Step 1: Install cylinder pressure and torsional vibration sensors on the engine body, install vibration sensors on engine wheel system accessories and other locations of interest throughout the vehicle, and install microphones at the driver's right ear and near the engine. Step 2: Drive the vehicle in second gear with constant throttle and accelerate slowly, and collect the first test data from the vibration sensor and microphone. Step 3: The vehicle is driven under starting and acceleration conditions, and second test data are collected from cylinder pressure and torsional vibration sensors, as well as vibration sensors and microphones. Step four: Perform spectrum analysis, wavelet analysis and modulation analysis on the second test data to determine the excitation source of the acceleration rough sound inside the vehicle, and analyze the key components at the engine source that contribute to the acceleration rough sound. Step 5: Use the Operational Transfer Path Analysis module of LMS software to build a vehicle model, import the first test data into the vehicle model, and calculate the initial transfer function on each transfer path. Step 6: Import the initial transfer function and the second test data into the vehicle model and calculate the main transmission path that contributes the most to the in-vehicle noise under the starting acceleration condition. Step 7: Optimize the materials and structure of the excitation source and structural components along the main transmission path to reduce rough acceleration noise inside the vehicle.

2. The accelerated roughness sound optimization method according to claim 1, characterized in that: In step one, the vehicle's key areas of focus include the suspension mounts and suspension brackets.

3. The accelerated roughness sound optimization method according to claim 1 or 2, characterized in that, The structural optimization in step seven specifically involves: locally reinforcing the structural components along the excitation source and main transmission path, or using dynamic vibration absorbers to attenuate the energy in the problem frequency range, in order to reduce the transmission of accelerated rough sound energy.

4. An accelerated rough sound optimization system, characterized in that, It enables the implementation of the steps of the accelerated roughness sound optimization method as described in any one of claims 1 to 3, including: The sensor module includes cylinder pressure and torsional vibration sensors arranged on the engine body, vibration sensors at engine wheel system accessories and other locations of interest in the vehicle, and microphones arranged at the driver's right ear and near the engine. The sensor module is connected to the data acquisition module. The data acquisition module is used to collect the first test data of the vibration sensor and microphone when the vehicle is driven in the second gear constant throttle slow acceleration condition, and to collect the second test data of the cylinder pressure and torsional vibration sensor, as well as the vibration sensor and microphone when the vehicle is driven in the start acceleration condition. The vehicle model creation module, namely the Operational Transfer Path Analysis module of the LMS software, is used to create the vehicle model. The analysis and calculation module performs spectrum analysis, wavelet analysis, and modulation analysis on the cylinder pressure, torsional vibration, vibration, and noise data in the second test data to clarify the generation mechanism of the rough sound source and analyze the key components that contribute to the engine source; it is used to import the first test data into the vehicle model and calculate the initial transfer function on each transmission path; the initial transfer function and the second test data are imported into the vehicle model to calculate the main transmission path of the vehicle that contributes the most to the in-vehicle noise under the starting acceleration condition; The evaluation module was optimized. The engine source gear system accessories were reduced by frequency avoidance and crankshaft stiffness improvement. The belt material and motor housing material were changed to avoid the rough sound frequency band. The forged steel crankshaft replaced the ductile iron crankshaft to reduce the source torsional vibration excitation by increasing the crankshaft stiffness. In terms of the whole vehicle path, the rough sound energy transmission was reduced by strengthening the body structure at the suspension connection. Regarding the final effect evaluation method, the interior roughness should not exceed 0.09 asper.

5. A storage medium, characterized in that: It contains a computer-readable program that, when invoked, can perform the steps of the accelerated coarse sound optimization method as described in any one of claims 1 to 4.

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