Method for identifying the contribution of in-vehicle noise during acceleration

Abstract

This invention discloses a method for identifying the contribution of in-vehicle noise during acceleration. The main design concept of this invention is to collect in-vehicle noise data at the target engine speed that generates in-vehicle boom noise during acceleration, thereby determining that it is second-order engine noise. Combined with expert knowledge, it is determined whether it is a structural sound path. After confirming that it is a structural sound path, the method uses the concept of Transmission Method Analysis (TPA), but does not use complex TPA modeling analysis. The mechanism for investigating the structural sound path is changed from the traditional methods of disconnection, counterweight, and component replacement to obtaining three specific parameters through NVH testing. This allows for low-cost processing and calculation to determine the contribution of the transmission path, thereby accurately identifying the main cause affecting the boom noise during acceleration, clarifying the problem path, guiding the direction of rectification, and proposing more refined noise reduction optimization measures based on the quantified contribution.

Description

Technical Field

[0001] This invention relates to the field of vehicle noise control technology, and in particular to a method for identifying the contribution of in-vehicle noise during acceleration. Background Technology

[0002] NVH is an abbreviation for Noise, Vibration and Harshness. Since these three factors occur simultaneously and are inseparable in mechanical vibration, they are often studied together.

[0003] With the rapid development of the automotive market, consumers have increasingly higher requirements for various performance aspects of automobiles, among which NVH (noise, vibration, and harshness) has become an important factor for consumers when choosing and purchasing cars.

[0004] Regarding vehicle noise, the roaring sound inside the vehicle during acceleration is one type of NVH problem. Severe roaring sounds can cause physical and mental discomfort, not only reducing vehicle comfort but also affecting driving safety.

[0005] Traditional approaches to troubleshooting vehicle NVH issues revolve around the "excitation source – transmission path – response" model. Reducing the excitation source or optimizing the transmission path can improve the in-vehicle response. Most vehicle NVH problems are solved by optimizing the transmission path, which is divided into airborne sound paths and structural sound paths. With the development of the automotive industry, the airtightness and acoustic tightness of vehicles have reached relatively high levels, and the main contributor to the roaring noise during acceleration is concentrated in the structural sound path.

[0006] Currently, troubleshooting the roaring noise inside the vehicle during acceleration relies on the experience of NVH engineers to conduct elimination tests on the main components affecting acceleration noise, such as by shielding, disconnecting, adding weights, or replacing parts to confirm the correlation of the problem. The drawback of this approach is that it relies too much on a single individual's experience, and purely manual judgment inevitably introduces uncontrollable risks.

[0007] On the other hand, the TPA (Transfer Path Analysis) method is used to establish a transfer path analysis model for the vehicle's acceleration conditions during the actual vehicle test. The model is then used to fit the noise level inside the vehicle, and the contribution of each excitation source and transfer path to this noise is analyzed. The main contributors are then rectified and optimized, resulting in high accuracy. However, this method also has its limitations:

[0008] First, the amount of data collected is large, and the accuracy requirements for the model are high, resulting in a huge workload.

[0009] Second, the requirements for matching test resources are high and difficult to meet. If the error of different groups needs to be reduced, the number of test rounds needs to be reduced, which leads to an increase in the number of channels of the required equipment.

[0010] Third, and most importantly, noise source separation and fitting are difficult to achieve and require high-end processing modules with high costs, which sets a threshold for implementation for most OEMs. Summary of the Invention

[0011] In view of the above, the present invention aims to provide a method for accelerating the identification of the contribution of in-vehicle noise under operating conditions, so as to solve the aforementioned technical problems.

[0012] The technical solution adopted in this invention is as follows:

[0013] This invention provides a method for identifying the contribution of in-vehicle noise under acceleration conditions, including:

[0014] Determine the target engine speed at which the in-vehicle roaring noise is generated under acceleration conditions;

[0015] The in-vehicle noise data is collected at the target engine speed, and the noise level is analyzed by spectrum and order to determine whether it is second-order engine noise.

[0016] After identifying it as second-order engine noise, the frequency of the in-vehicle noise data at the target engine speed is obtained, and expert knowledge is used to determine whether it is a structural sound path.

[0017] After the structural acoustic path is determined, the in-vehicle response expression of the structural acoustic path at the target engine speed is obtained through a preset transmission path analysis strategy. The in-vehicle response expression includes the excitation force and the structural transfer function.

[0018] The excitation force is characterized by vibration acceleration and acceleration admittance, and the structural transfer function of each original excitation point is characterized by acoustic-vibration sensitivity.

[0019] The experiment yielded three parameters: vibration acceleration, acceleration admittance, and acoustic sensitivity at each original excitation point in several structural acoustic paths to be investigated.

[0020] The three parameters mentioned above are converted into a unified numerical unit, and the contribution of each structural acoustic path is obtained by summation calculation.

[0021] In at least one possible implementation, the identification method further includes: sorting the contribution of each structural acoustic path to be investigated, and determining the noise reduction target based on the sorting result.

[0022] In at least one of the possible implementations, obtaining the three parameters of each original excitation point includes: obtaining the vibration acceleration, acceleration admittance characterization, and acoustic-vibration sensitivity of each original excitation point in the X, Y, and Z directions, respectively.

[0023] In at least one of the possible implementations, characterizing the excitation force as vibrational acceleration and acceleration admittance includes converting the excitation force into a product of acceleration and acceleration impedance.

[0024] In at least one possible implementation, determining whether it is a structured acoustic path includes: confirming whether the radiated noise of the airborne acoustic path is within the target requirements.

[0025] In at least one of the possible implementations, the acquisition of in-vehicle noise data at the target engine speed includes: acquiring noise data in the driver's ear area.

[0026] The main design concept of this invention is to collect in-vehicle noise data at the target engine speed that generates in-vehicle boom noise under acceleration conditions, thereby determining that it is second-order engine noise. Combined with expert knowledge, it is determined whether it is a structural sound path. After confirming that it is a structural sound path, the mechanism for investigating the structural sound transmission path is changed from the traditional methods of disconnection, counterweight, and component replacement to obtaining three specific parameters through NVH testing, using the concept of TPA but without using complex TPA modeling analysis. This allows for low-cost processing and calculation to determine the contribution of the transmission path, thereby accurately identifying the main cause affecting the acceleration boom noise, clarifying the problem path, guiding the direction of rectification, and proposing more refined noise reduction optimization measures based on the quantified contribution. Attached Figure Description

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below with reference to the accompanying drawings, wherein:

[0028] Figure 1 A flowchart of a method for identifying the contribution of in-vehicle noise under acceleration conditions provided in an embodiment of the present invention. Detailed Implementation

[0029] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0030] This invention proposes an embodiment of a method for identifying the contribution of in-vehicle noise under acceleration conditions. Specifically, as follows: Figure 1 As shown, it includes:

[0031] Step S1: Determine the target engine speed at which the in-vehicle roaring noise is generated under acceleration conditions;

[0032] Step S2: Collect in-vehicle noise data at the target engine speed, and determine whether it is engine second-order noise through spectrum and order analysis.

[0033] Step S3: After determining that it is second-order engine noise, obtain the frequency of the in-vehicle noise data at the target engine speed, and combine it with expert knowledge to determine whether it is a structure sound path.

[0034] Step S4: After determining the structural acoustic path, the in-vehicle response expression of the structural acoustic path at the target engine speed is obtained through a preset transfer path analysis strategy (TPA). The in-vehicle response expression includes the excitation force and the structural transfer function.

[0035] Step S5: Characterize the excitation force with vibration acceleration and acceleration admittance, and characterize the structural transfer function of each original excitation point with acoustic vibration sensitivity.

[0036] Step S6: Obtain the three parameters—vibration acceleration, acceleration admittance, and acoustic sensitivity—at each original excitation point in several structural acoustic paths to be investigated through NVH testing.

[0037] Step S7: Convert the three parameters mentioned above into a unified numerical unit, and obtain the contribution of each structural acoustic path as quantified by summation calculation.

[0038] Taking a certain model as an example, based on expert experience, it is determined that a severe roaring sound will be produced when accelerating to 3300rpm. Therefore, the roaring sound at 3300rpm needs to be resolved (the roaring sound that reappears at other speeds such as 4000rpm can be handled in the same way).

[0039] In actual operation, by collecting noise data heard by the driver (e.g., at the right ear) and through spectrum and order analysis, it was confirmed that the ear-pressing roaring sound generated in the car at 3300 rpm was the second-order noise of the engine.

[0040] Next, using the formula The frequency corresponding to the second-order noise at 3330 rpm is 111 Hz, where f is the frequency (Hz) and n is the engine speed (r / min).

[0041] Therefore, the peak noise at 3300 rpm has a low frequency and high energy. Based on expert experience, the problem is judged to be structural resonance, meaning the main path is one or more structural sound paths. Ideally, the radiated noise from the engine's near-field, intake, and exhaust ports should be verified to be within the target requirements, thus eliminating airborne sound paths.

[0042] For the investigation of structural sound paths, the in-vehicle response can be obtained by using the basic principles of TPA. Specifically, the in-vehicle response can be represented by the following formula (1).

[0043]

[0044] Where P represents the in-vehicle response, F i Let H be the structural load along the i-th path, i.e., the original excitation force. i Let be the structural transfer function for the i-th path. This formula means that the in-vehicle noise is the vector sum of the product of the structural loads and the transfer functions for each path.

[0045] In actual operation, the structural load, i.e. the original excitation force, is difficult to obtain in the experiment. Therefore, the excitation force can be converted into the product of acceleration and acceleration impedance, expressed by formula (2).

[0046] (IPI, acceleration admittance, is the ratio of acceleration to excitation force), and IPI can be directly obtained through existing NVH tests. It should be added here that 1 / IPI is the dynamic stiffness at the origin.

[0047] H in formula (1) i The structural transfer function is represented by the acoustic sensitivity (NTF) in NVH, which is the ratio of the sound inside the vehicle to the applied excitation force, and can be expressed by the following formula (3).

[0048]

[0049] Next, by combining the above formulas (1), (2), and (3), formula (4) can be derived mathematically:

[0050]

[0051] To more intuitively express the relationship between the parameters, (4) can be transformed into the following formula (5):

[0052]

[0053] Where 'a' represents vibration acceleration in g; IPI represents acceleration admittance in g / N; and NTF represents acoustic-vibration sensitivity in dB / N or Pa / N. The reason for using these three parameters to characterize the in-vehicle response, as explained above, is that these three parameters are relatively easy to obtain in NVH testing.

[0054] Next, by using the logarithmic formula lgA·B·C=lgA+lgB+lgC, the logarithm of both sides of formula (5) can be taken. Only by converting a, IPI, and NTF into a unified numerical unit (decibels) can the contribution of the structure sound path be obtained by summation calculation, and then the contribution ranking of each structure sound path can be easily obtained.

[0055] Based on the above explanation and the aforementioned vehicle model example, the engine's three mounting points, the four mounting points of the subframe and body, and the right driveshaft axle head can be selected as the original excitation points. The aforementioned three parameters at 3300 rpm can be obtained for each original excitation point. Specifically, the aforementioned three parameters in the X, Y, and Z directions can be further refined for each original excitation point. Thus, through actual measurement and calculation, the sum of the contributions of each structural sound path in this example can be listed and sorted. From this, the structural paths with the greatest impact can be intuitively identified, such as the right mounting point in the Z direction, the right rear subframe mounting point in the Z direction, and the right axle head in the X direction. Therefore, based on this sorting result, a 112Hz vibration absorber can be added to the right mounting point (right longitudinal beam), and a 114Hz vibration absorber can be added to the right axle head for real-vehicle verification, thereby completing the noise reduction task at 3300 rpm.

[0056] In summary, the main design concept of this invention is to collect in-vehicle noise data at the target engine speed that generates in-vehicle boom noise under acceleration conditions, thereby determining that it is second-order engine noise. Combined with expert knowledge, it is determined whether it is a structural sound path. After confirming that it is a structural sound path, the structural transmission path investigation mechanism is changed from the traditional methods of disconnection, counterweight, and component replacement to obtaining three specific parameters through NVH testing, using the TPA concept but without using complex TPA modeling analysis. This allows for low-cost processing and calculation to determine the contribution of the transmission path, thereby accurately identifying the main cause affecting the acceleration boom noise, clarifying the problem path, guiding the direction of rectification, and proposing more refined noise reduction optimization measures based on the quantified contribution.

[0057] In this embodiment of the invention, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, A and B simultaneously, or B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, at least one of a, b, and c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

[0058] The above description of the structure, features, and effects of the present invention is based on the embodiments shown in the figures. However, the above are only preferred embodiments of the present invention. It should be noted that the technical features involved in the above embodiments and their preferred methods can be reasonably combined and matched by those skilled in the art to form a variety of equivalent solutions without departing from or changing the design concept and technical effects of the present invention. Therefore, the present invention is not limited to the scope of implementation shown in the figures. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments, that do not exceed the spirit covered by the specification and figures, should be within the protection scope of the present invention.

Claims

1. A method for identifying the contribution of in-vehicle noise during acceleration, characterized in that, include: Determine the target engine speed at which the in-vehicle roaring noise is generated under acceleration conditions; The in-vehicle noise data is collected at the target engine speed, and the noise level is analyzed by spectrum and order to determine whether it is second-order engine noise. After identifying it as second-order engine noise, the frequency of the in-vehicle noise data at the target engine speed is obtained, and expert knowledge is used to determine whether it is a structural sound path, including: confirming whether the radiated noise of the airborne sound path is within the target requirements to exclude the airborne sound path. After the structural acoustic path is determined, the in-vehicle response expression of the structural acoustic path at the target engine speed is obtained through a preset transmission path analysis strategy. The in-vehicle response expression includes the excitation force and the structural transfer function. The excitation force is characterized by vibration acceleration and acceleration admittance, and the structural transfer function of each original excitation point is characterized by acoustic-vibration sensitivity. The experiment yielded three parameters: vibration acceleration, acceleration admittance, and acoustic sensitivity at each original excitation point in several structural acoustic paths to be investigated. The three parameters mentioned above are converted into a unified numerical unit, and the contribution of each structural acoustic path is obtained by summation calculation. The specific quantization method is implemented according to the following summation algorithm: lg vibration acceleration × (1 / acceleration admittance) × acoustic vibration sensitivity = lg vibration acceleration + lg(1 / acceleration admittance) + lg acoustic vibration sensitivity.

2. The method for identifying the contribution of in-vehicle noise during acceleration as described in claim 1, characterized in that, The identification method further includes: sorting the contribution of each structural acoustic path to be investigated, and determining the noise reduction target based on the sorting result.

3. The method for identifying the contribution of in-vehicle noise during acceleration as described in claim 1, characterized in that, The three parameters obtained for each original excitation point include: vibration acceleration, acceleration admittance characterization, and acoustic-vibration sensitivity in the X, Y, and Z directions for each original excitation point.

4. The method for identifying the contribution of in-vehicle noise during acceleration as described in claim 1, characterized in that, The description of the excitation force as vibration acceleration and acceleration admittance includes converting the excitation force into the product of acceleration and acceleration impedance.

5. The method for identifying the contribution of in-vehicle noise during acceleration as described in any one of claims 1 to 4, characterized in that, The in-vehicle noise data collected at the target engine speed includes: noise data collected in the driver's ear area.

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