Browse Topic: Interior noise

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Assessment of Structure-borne Road Noise for Battery Electric Vehicle: Prediction and Improvement2026-26-03201/16/2026
In the absence of engine noise, road-induced noise has become a major concern specifically for Battery Electric Vehicles (BEVs), impacting Sound Pressure Level (SPL) for both drivers and passengers. Under the influence of random road load inputs, structural vibrations which transfer from road and tire to suspension to vehicle body, the cabin interior noise, particularly at lower frequencies, is significantly affected. To improve the road-induced low-frequency structure-borne noise behaviour, which frequently perceptible as ‘booming noises’, a study was carried out to assess predominant noise sources present in vehicle and to suggest refinements in reducing noise levels. By considering random excitations of road profile through tyre patch using CD-Tire model, vehicle interior noise was computed. Subsequently, to get insight of dynamic behaviour of vehicle, various diagnostic assessments to understand the influence from structure and paths were deployed. Major contributors from body
Paik, Dr. Suman, Raghuvanshi, Jayeshkumar, Chaudhari, Vishal Vasantrao, V, Radhika
Assessment and Auralization of Cabin Noise from AVAS Operation in an Electric Vehicle Using a Hybrid BEM–SEA Methodology2026-26-03571/16/2026
In electric and hybrid vehicles, sound package optimization can follow a classical, proven, and structured approach for real-world loads, while also considering new transmission paths that might differ from those in traditional internal combustion engine vehicles. However, AVAS-induced interior noise is sometimes underestimated and therefore not taken into account during the optimization process. Nevertheless, especially at very low speeds, the presence of the AVAS can be perceived as an unwanted noise inside the vehicle, potentially compromising interior comfort. In this study, a hybrid boundary element–statistical energy analysis (BEM – SEA) approach is applied to an SEA dual-motor electric vehicle demonstrator model equipped with a baseline, standard sound package to assess AVAS-induced interior noise. A standard AVAS actuator is modeled, and a BEM model is used to compute the sound pressure levels on the exterior subsystems of the vehicle. These results are then transferred to the
Fiedler, Robert, Calloni, Massimiliano, Martin, Simon
Resolution of Automotive Air Compressor Noise in Low Powered ICE vehicle2026-26-03141/16/2026
Passenger compartment's interior noise and thermal performance are one of the essential criteria for the driving comfort of vehicles. This paper explains that how the AC compressor noise is optimized in specific to low powered 1 L - ICE engine and 120 cc IVDC compressor combination. This combination is quite challenging due to high operational load & higher operating pressure. For better in-cabin cooling efficiency, compressor operating efficiency to be improved which in turn leads to higher displacement of the compressor. Higher displacement will lead to higher internal forces which leads to more structure borne induced noise in-side the cabin. For this specific combination, the compressor operating pressure reached to 25 bar at most of the driving condition. During dynamic driving condition, compressor metallic tonal noise was reported in one of the A segment vehicle developments. It was reported as very annoying to inside passenger. Transfer Path Analysis, Compressor fixation point
John Britto, Vijay Antony, Maluganahalli-Dharmappa Madhusoodan Sr, 1Lt Madhusoodan, Natarajasundaram, Balasubramanian
Experimental Frequency-Based Substructuring for Full-Vehicle NVH Characterization in Electric Vehicles2026-26-03091/16/2026
Electric vehicles introduce new NVH challenges due to high-frequency excitations from e-motors and associated electronics. These excitations, often in the kilohertz range, are primarily transmitted as structure-borne noise and require advanced experimental methods for accurate characterization and mitigation. Traditional simulation approaches are insufficient to capture the true dynamic behavior of complex components under operational boundary conditions. This study presents a fully experimental Frequency-Based Substructuring (FBS) methodology applied to a complete electric vehicle. Frequency Response Functions (FRFs) of individual subsystems—such as the e-motor, mounting system, inverter housing, and body connection points—are measured and transformed using Virtual Point Transformation to obtain consistent six-degree-of-freedom representations. These Virtual Point models are assembled into a full-vehicle system to investigate the structure-borne transfer paths to the vehicle interior
Kohlhofer, Daniel, Pingle, Pawan Sharad, de Klerk PhD, Dennis
Tractor Cabin Structure Borne Noise Reduction in the Virtual Environment2026-26-01011/16/2026
In recent days, cabin variants in the tractor are preferred by the farmers for the Coziness and longer field hour operation with less fatigue. Noise perceived by customer is the most important factor taken into account during the design stage, as it’s directly linked with operator’s comfort. Observed noise levels has to be within the defined limits as per national/international standards Overall cabin noise levels is contributed by the structure borne noise below 630 Hz. Structure borne noise is the noise typically radiated by the door, roof, windshield, floor, fender and structure assembly due to the engine excitation through the transmission housings and backstories. This paper depicts the process of tractor cabin structure borne noise prediction in the virtual environment. Firstly, Engine bearing loads and axle bearings has been extracted in the virtual stage from the vehicle level driveline model using commercially available MBD software. The finite element (FE) model of the cabin
gunasekaran, pandiyanayagam, K, Somasundaram, Chavan, Amit
Sound quality refinement and vibration reduction during Horn Application in Electric Vehicles2026-26-03381/16/2026
This paper focuses on the cabin sound quality refinement and the tactile vibration reduction during horn application in the electric vehicle. Horn cracking sound is perceived in the cabin while pressing the horn. Higher vibrations are also perceived in accelerator pedal during the particular event. Sound diagnosis is carried out to identify the frequencies contributing to cracking noise. Transfer path analysis is conducted to identify the nature of noise and the predominant path through which forces transfer. Based on finding from TPA, various recommendations are evaluated which reduced the noise to a certain extent. Operational Deflection Shape(ODS) is conducted on the horn, horn mounting bracket and on the body to identify the component having higher deflection at the problematic frequencies . Based on the outcome of ODS, recommendations like dynamic stiffness improvement on the horn bracket and the body is assessed and the effect of each outcome is discussed. With all the
S, Nataraja Moorthy
Investigation and Reduction of Road Noise due to transient road inputs in Electric Vehicle2026-26-03581/16/2026
Higher road noise is perceived in the cabin when the test vehicle encounters road irregularities like bump or pothole in the public roads. The sudden transfer of transient road inputs inside the body caused objectionable cabin noise. Measurements are conducted on the test track at different road surfaces to identify the patch where the objective data well correlated with the noise measured at the public road. Wavelet analysis is carried out to identify the frequency zones since the events are transient in nature. Transfer Path Analysis (TPA) is conducted in both time domain and frequency domain to identify the nature of the noise and the limitation in each of the methodologies are explained. The dominant path through which the transient road forces are transferring inside the body are also identified. Based on the outcome of TPA, various countermeasures like reduction of dynamic stiffness of suspension and cradle bushes , structural modifications on the path are proposed to reduce the
S, Nataraja Moorthy
Investigation of Low Frequency Interior Noise due to Tyre-Road Interaction2026-26-03511/16/2026
Unlike internal combustion engine (IC Engine) vehicles, the rapidly growing electric vehicle (EV) market demands tyres with superior yet often conflicting performance characteristics. The increased weight of EVs, due to their heavy batteries, necessitates robust tyres with reinforcement and higher inflation pressure. Conversely, increased wear due to higher initial torque and the need for lower rolling resistance to extend range, combined with the requirement for better grip for improved handling, call for advanced compound and tread pattern designs. EV tyres need to be stiffer, lighter, and less dampened, making it very hard to reduce low-frequency (20-200 Hz) interior noise that was previously hidden by engine noise. This study investigates the low-frequency (20-200 Hz) structural-borne interior noise performance of EV tyres using both experimental and simulation tools. By wisely tuning the tyre's stiffness, mass, and damping properties, the necessary noise targets can be met. These
Subbian, Jaiganesh, M, Saravanan
Use of Statistical Energy Analysis to predict Articulation Index (AI) in a vehicle interior for real- world operating scenarios.2026-26-04301/16/2026
Vehicle interior noise is a crucial assessment criterion for automotive NVH. It has a significant effect on customer opinions about the quality of a vehicle. Articulation Index (AI) is one of the key sound metrics used to describe speech intelligibility and quantifies the middle and high frequency spectra associated to the internal noise of vehicle. In reality, Vehicle operating under dynamic condition experiences various air-borne noise sources such as tire rolling noise, powertrain noise, intake-exhaust noise & wind noise along with structure borne excitations such as powertrain vibrations, suspension vibrations. It is very challenging to predict cumulative effect of all these excitations to interior noise level and Articulation Index (AI) of vehicle over complete frequency range. The statistical energy analysis (SEA) is a well-known methodology being used to simulate & predict mid & high frequency noise. Objective of this paper is to present the process of development of a SEA
Doijad, Vishwajit Padmakar, Billade, Dayanand, Apte Sr., Amol Arun, Shewale, Amol, Kothapalli, Brahmananda Reddy
Analysis of door seal compression and its influence on NVH performance in heavy-duty vehicle2026-26-03391/16/2026
Seals in a truck cabin is one of the major contributors for cabin noise in terms of structure borne as well as air borne noise transfer path. This study emphasizes on the effect of door seal compression prediction and its impact on structure borne NVH in trucks. Vibrations are regarded as quality criteria in the perception of customers. It is necessary to ascertain the contribution of seal stiffness on compression of the seal under closed condition of the door rather than uncompressed conditions. The dynamic stiffness of door seal is calculated by non-linear analysis. The simulations models are constructed using the Mooney - Rivlin theory for both 2D and 3D seals. This encompasses contemplating the relevant seal mounted boundary condition on the body and the door of the vehicle. The stiffness after compression of seal is extracted from this non-linear analysis which is further used to obtain the vibration modes for the doors in the truck cabin. Subsequently, the compressed seal
L, Kavya, Ramanathan, Vijay
Low idle boom noise reduction on Light Weight Agricultural Cabin Tractor2026-26-01001/16/2026
In Last two decades, Farm customer expectation on Cabin comfort has been increased multifold. To provide the best-in-class customer experience in terms of comfort without adding cost and weight is bigger challenge for all NVH Engineers. It is evident from literature survey that cabin tractors with better comfort is well accepted by customers in US and European Market. Apart from engine excitation, customer has become more sensitive to customer-actuated-accessory noises due to overall reduction in cabin noise in last 2 decades. This paper presents the study conducted on HVAC blower noise in 30HP cabin tractor Tactile vibrations and Cabin Noise is not acceptable when AC is switched on due to low frequency modulating nature in frequency range of ~65Hz and 130Hz. The investigation is carried out systematically considering each component of Source-Path-Receiver model. HVAC blower unit as source is diagnosed in detail to understand root cause. Strong dominance of first order of blower been
K, Somasundaram, Chavan, Amit
Blade Stiffened Carbon/Epoxy Panels with Longitudinally Tapered Acoustic Black Holes for Vibration ReductionF-0081-2025-02765/20/2025
Carbon/epoxy stiffened panels are being increasingly used in transport rotorcraft. The reduced mass density and high stiffness of carbon/epoxy composites can lead to higher levels of vibration relative to comparable metallic structures, which themselves can have vibrations and interior noise high enough to damage the hearing of crew and passengers. The current investigation explores a method to reduce the vibration of carbon/epoxy stiffened panels by introducing thickness tapers known as acoustic black holes (ABHs). The ABH feature is integrated into either the stiffeners or plate of a representative stiffened panel configuration. A finite element (FE) parametric study was used to guide designs that reduce the vibration of the panel without compromising the compressive buckling capability or mass of the panel. FE studies showed that a 30 ply to 12 ply thickness taper longitudinally oriented in the blade stiffener can reduce vibrations and increase compressive buckling capability
Brown, Avery, Patel, Bhavya, Robertson, Noah, Bakis, Charles, Smith, Edward, Beck, Ben, Shepherd, Micah, Vlajic, Nicholas
Circular Acoustic Black Holes Integrated into Carbon/Epoxy Stiffened Panels for Noise ControlF-0080-2024-12455/7/2024
Carbon fiber reinforced epoxy composite stiffened panels are increasingly being used for structural components in large transport rotorcraft. However, problems are arising with high levels of vibration and interior noise due to the increased stiffness-to-density ratio of composites. The current investigation explores the potential of reducing vibrations in carbon/epoxy stiffened panels with the integration of acoustic black holes (ABH), namely features that incorporate a power law thickness taper. The proposed approach involves designing a taper into the thickness of the blade stiffeners as well as the thin plate. Integration of ABHs into the fuselage structure has the potential to reduce broadband vibrations. Multiple parametric studies with either an ABH integrated into the blade stiffener or a grid of ABHs integrated into the plate were conducted, and the tradeoffs between vibration amplitudes, panel mass, and compressive buckling load were examined. Carbon/epoxy panels were
Brown, Avery, Vlajic, Nicholas, Shepherd, Micah, Beck, Ben, Smith, Edward, Bakis, Charles, Robertson, Noah, Patel, Bhavya
Electric vehicle road noise analysis through systematic virtual prototyping2024-26-02241/16/2024
Without the masking effect of a combustion engine, noise from the road is much more prominent in electric vehicles (EV) and has become the dominant source of noise for drivers and passengers. Road noise however is a complex problem. Unlike engine noise, which comes from a single, well-defined source, road noise finds its origins in the road-to-tire contact. This means that there are typically 4 sources (assuming a 4-wheel vehicle) which are influenced by the roughness and profile of the road as well as the compliance of the tires. From an engineering point of view it’s easy to appreciate the added complexity compared to engine noise. In addition to the engineering complexity, there is also a supplier-OEM relationship that comes into play. Most OEMs do not manufacture their own tires and may even have multiple tire suppliers for the same vehicle. This brings on another set of complications. Firstly, there are multiple types of tires for the same vehicle, each combination having its own
Dom, Steven, Van Genechten PhD, Bert, Sorber, Eric, Minervini, Domenico
Investigating The Factors Affecting Cabin Comfort for Agricultural Machinery2024-26-00671/16/2024
Customer expectations for cabin tractors from comfort perspective has grown multifold in the recent years. Cabin noise and vibration is one of the crucial parameter which drives comfort feel for the customer. This would enable customer to remain comfortable during long working hours. Moreover, Cabin Tractors with lesser noise levels found to have better acceptance by Customers all over the world. The Nebraska reports studied for US based tractor shows evolution of trend of cabin noise in 100-150hp tractors in last couple of decades. Undoubtedly, tractor manufacturers have put lot of efforts towards meeting legislation demand & stringent customer requirements for European and US market. This paper presents the work carried out for investigating major contributing factors affecting tractor cabin Noise & Vibration for an existing 75HP tractor. Virtual and experimental studies have been carried out to identify the principal source of noise and the transfer paths for cabin noise
Chavan, Amit, K, Somasundaram, gunasekaran, Pandiyanayagam, Chaudhari, Vishal V, Sati, Navin
Countermeasures for Low Frequency Boom noise Reduction in Electric Vehicle2024-26-02141/16/2024
Electric vehicles are much quieter than IC engine powered vehicles due to less mechanical components and absence of combustion. The lower cabin noise in electric vehicles make customers sensitive to even small disturbance in vehicle. Road boom noise is one of the major concerns to which the customers are sensitive in electric vehicles. The test vehicle is a front wheel driven compact SUV powered by electric motor. In normal plain road, noise levels are acceptable but when the vehicle has been driven on coarse road, the boom noise is perceived, and the levels are objectionable. Multi reference Transfer path Analysis (MTPA) is conducted to identify the path through which maximum forces are entering the body. Based on MTPA, modifications are proposed on the suspension bushes and the noise levels were assessed. Operational deflection shape (ODS) analysis is conducted on entire vehicle components like suspension links, sub frame, floor, roof, and doors to identify the deflection pattern of
S, Nataraja moorthy, Rao, Manchi, Raghavendran, Prasath, Selvam, Ebinezer
Analysis and Reduction of Abnormal Suspension Noise in Sports Utility Vehicle2024-26-02171/16/2024
This paper focuses on reducing abnormal noise originating from suspension when driving on rough road at the speed of 20 kmph. The test vehicle is a front wheel driven monocoque SUV powered by four cylinder engine. Cabin noise levels are higher between 100 to 800 Hz. Vibration levels are measured on front and rear suspension components, front and rear subframe, subframe connections on body to identify the noise source locations. Since the noise levels are dominant only in certain rough patches at very narrow band of time, wavelet analysis is used for problematic frequency identification. Based on wavelet analysis, it is identified that the vibration levels are dominant on front lower control arm (LCA) due to inferior isolation performance. The dynamic stiffness of LCA bushes is reduced by ~ 30% to improve the isolator performance which reduced the noise levels by ~ 2 dB (A). Modal analysis is conducted on suspension components like LCA, stabiliser bar, shock absorber, tires and front
S, Nataraja Moorthy, Rao, Manchi Venkateswara, Raghavendran, Prasath, Manivannan, Giridharan
Experimental Investigation into Modulated Aeroacoustic Cabin Noise arising from Unsteady Flow Conditions2025-01-00295/5/2023
The unsteady wind conditions experienced by a vehicle whilst driving on the road are different to those typically experienced in the steady-flow wind tunnel development environment, due to turbulence in the natural wind, moving through the unsteady wakes of other road vehicles and travelling through the stationary wakes generated by roadside obstacles. This paper presents the use of experimental approach using an SUV-shaped vehicle to assess the effect of unsteady wind on the modulated noise performance, commonly used to evaluate unsteady wind noise characteristics. The approach is extended to assess the pressure distribution on the front side glass of the vehicle, caused by the aerodynamic interactions of the turbulent inflow, to provide insight into the noise generation mechanisms and differences in behaviour between the two environments. The vehicle response to unsteady wind conditions was assessed using two approaches: a dynamic upstream unsteady flow the using active side wind
Jamaluddin, Nur Syafiqah, Oettle, Nicholas, Staron, Domenic
Leveraging user feedback to optimize the tuning of EVSE models2025-01-00205/5/2023
The implementation of active sound design models in vehicles requires precise tuning of synthetic sounds to harmonize with existing interior noise, driving conditions, and driver preferences. This tuning process is often time-consuming and intricate, especially facing various driving styles and preferences of target customers. Incorporating user feedback into the tuning process of Electric Vehicle Sound Enhancement (EVSE) offers a solution. A user-focused empirical test drive approach can be assessed, providing a comprehensive understanding of the EVSE characteristics and highlighting areas for improvement. Although effective, the process includes many manual tasks, such as transcribing driver comments, classifying feedback, and identifying clusters. By integrating driving simulator technology to the test drive assessment method and employing machine learning algorithms for evaluation, the EVSE workflow can be more seamlessly integrated. But do the simulated test drive results
Hank, Stefan, Kamp, Fabian, Gomes Lobato, Thiago Henrique
Cabin noise modeling for seat location variation using AI and Machine Learning2025-01-01295/5/2023
Analyzing acoustic performance in large and complex assemblies, such as vehicle cabins, can be a time-intensive process, especially when considering the impact of seat location variations on noise levels. This paper explores the use of AI and machine learning to streamline this analysis by predicting the effects of different seat configurations on cabin noise, particularly at the driver’s ear level. The study begins by establishing a baseline simulation of cabin noise and generating training data for various seat location scenarios. This data is then used to train an AI model capable of predicting the noise impact of further seat adjustments. These predictions are validated through detailed simulations. The paper discusses the accuracy of these predictions, the challenges encountered, and provides insights into the effective use of AI and machine learning in acoustic analysis for cabin noise, with a specific emphasis on seat location as a key variable. Keywords: Acoustic analysis, AI
Kottalgi, Santosh, Banerjee, Bhaskar
Characterization and Prediction of Interior Noise Quality in Electric Vehicles through Drive Unit End-of-Line Testing (EOLT)2025-01-00395/5/2023
This paper addresses the critical aspect of interior noise quality in electric vehicles (EVs), focusing on the characterization and prediction methodologies employed during drive unit end-of-line testing. The electric drive unit plays a pivotal role in determining the overall Noise, Vibration, and Harshness (NVH) quality of the final product. This study explores the impact of drive unit assembly process variation and individual component tolerance on the NVH characteristics of electric drive units, emphasizing their direct effect on overall vehicle acoustic quality and customer comfort. The research delves into the intricate relationship between drive unit vibrational response, vehicle interior noise, and customer subjective perception, providing valuable insights into their correlation and how they collectively influence user experience and satisfaction. It aims to enhance the understanding of how electric drive unit characteristics contribute significantly to the interior noise
Arvanitis, Anastasios, Parbat, Aniket, Jadhav, Prashant, Raphael, Andrew
Underbody contribution simulation for vehicle wind-noise.2025-01-00265/5/2023
Wind noise is one of the largest sources to the interior noise of modern electric and hybrid vehicles. This noise is encountered when driving on roads and freeways from medium speed and generate considerable fatigue for passengers on long journeys. Aero-acoustic noise is the result of turbulent and acoustic pressure fluctuations created within the flow. They are transmitted to the passenger compartment via the vibro-acoustic excitation of vehicle surfaces and underbody cavities. Generally, this is the dominant flow-induced source at low frequencies. The transmission mechanism through the vehicle floor and underbody is a complex phenomenon as the paths to the cavity can be both airborne and structure-borne. This study is focused on the floor contribution to wind noise of different type of vehicles (SUV and Sport car), whose underbody structure are largely different. Aero-Vibro-acoustic simulations are performed to clarify the transmission mechanism of the underbody wind noise and
Mordillat, Philippe, Zerrad, Mehdi, Errico, Fabrizio
A computational process to predict and mitigate liftgate gap noise2025-01-00285/5/2023
Noise comfort significantly influences vehicle purchasing decisions. With wind noise being a primary contributor to the overall cabin experience vehicle manufacturers must focus on optimizing the exterior shape of their models to minimize wind noise while balancing fuel efficiency and aesthetic appeal. High-speed airflow over gaps in the vehicle’s exterior can generate considerable noise, which often enters the cabin through seals. A good sealing strategy could be very helpful to address these gap noise issues. However, doing this with traditional experimental processes can be challenging, since early stage prototypes may lack detailed gap information. Modifying the seal design after the tooling stage to address these noise issues can be costly for manufacturers, as suppliers often incur expenses related to tool modifications and redesigns. Overdesigning by incorporating multiple layers of seals for all the gaps can inflate part and manufacturing costs, ultimately impacting profit
Moron, Philippe, Jantzen, Andreas, Kim, Minsuk, Senthooran, Sivapalan
Interior Noise Reduction of Construction Equipment Vehicle Through Structure-borne Noise Reduction Strategy2025-01-00635/5/2023
One can witness the constant development and redevelopment of cities throughout the world. Construction equipment vehicles (CEVs) are commonly used on the construction site. However, the noise pollution from construction sites due to the use of CEV has become a major problem for many cities. The construction equipment employed is one of the main causes of these elevated noise levels. The construction workers possibly are face a potential risk to their auditory health and well-being due to the noise levels they are exposed to. Different countries have imposed exterior and operator noise limits for construction equipment vehicles, enabling them to control noise pollution from CEVs. In this study, the operator ear level noise of the identified vehicle is 6 dB(A) higher than the regulatory limit in dynamic conditions, when tested as per ISO 6396. It was a tough time for the NVH engineer to reduce the interior noise level of the vehicle. Surprisingly, the steering unit and radiator fan were
Jawale, Pradeep
Correlated beamforming based on deconvolution methods for identified vehicle exterior wind noise sources and interior noise2025-01-00255/5/2023
Sound source identification based on beamforming is widely used today as a spatial sound field visualization technology in wind tunnel experiments for vehicle development. However, the conventional beamforming technique has its inherent limitations. To improve the performance, three deconvolution methods CLEAN, CLEAN-SC and DAMAS were investigated. These algorithms were applied for the wind noise sources identification on a production car. After analysis of vehicle exterior wind noise sources distribution, to study the energetic contribution of identified exterior noise sources to interior noise, correlation analysis between them were conducted. The results show that, the algorithm CLEAN-SC based on spatial source coherence shows the outstanding capability to remove the sidelobes for the uncorrelated wind noise sources, while CLEAN and DAMAS which based on point spread function have definite limitations. In the application aspect, the main noise source outside vehicle is from the
He, Yinzhi, Shen, Henghao, Wu, Yu, Zhang, Lijun, Yang, Zhigang
HV-BATTERY IMPACT ON CAR BODY ACOUSTICS AND DAMPING PACKAGE OPTIMIZATION OF THE ELECTRIC VEHICLE2025-01-00415/5/2023
Damping treatments are playing an important role in the definition of efficient acoustic packages for passenger cars with all types of propulsion systems. Many parts of the damping layout are identical for all vehicles including treatments of wheelhouses, spare wheel area, roof panels etc. However, there are some characteristics in car body acoustics associated with the presence of the battery in electric vehicles, which need to be considered in the definition of the efficient damping package. The presented paper investigates the impact of the HV-battery on interior noise related characteristics of the car body using laser scanning vibrometry and 3D acoustic intensity test methods. Findings are used in the subsequent optimization of the initial damping package resulting in various package proposals with different lightweight and acoustic requirements. New damping package variants are evaluated in the lab by laser vibrometry tests and the impact on interior noise is addressed by road
Unruh, Oliver, Gielok, Martin
Reducing LiDAR Cabin Noise with Damped Elastomers: a Novel Method for Predicting Performance and Durability2025-01-01145/5/2023
Mechanical LiDAR units utilize spinning lasers to scan surrounding areas to enable limited autonomous driving. The motors within the LiDAR modules create noise that can leak into the cabin of a vehicle. Decoupling the module from the body of the vehicle with highly damped elastomers can reduce the acoustic noise in the cabin and improve the driving experience. Damped elastomers work by absorbing the vibrational energy and dispelling it as latent heat, which creates challenges in an unpredictable automotive environment. Throughout the development process with vehicle OEMs and LiDAR ODMs, highly damped elastomers were able to effectively reduce the noise created by the scanning LiDAR modules in a laboratory environment. It was unproven that these elastomers would be as effective in extreme heat, cold, or humid environments. Extensive bench and vehicle tests were conducted, but confidence was low without a model to predict behavior at edge-cases. By creating a unique test method to model
Russell, Casey, Masterson, Peter, O'Connell, Kerry
Differential Assembly Abnormal Noise Diagnosis Analysis and Optimization for the Electric Vehicle Steering Operation at Low Speed Cruise2022-01-07823/29/2022
With the improvement of vehicle comfort requirements of market users, NVH performance has been paid more and more attention. Especially the pure electric passenger vehicle is lack of combustion engine noise masking effect, it is more likely to cause the drivers attention for any abnormal noise. In the steering operation under the low speed acceleration of pure electric vehicles, the cabin interior noise derived from the road and the wind is relatively low, and there is not marketing effect of traditional internal combustion engine noise, any slight abnormal noise is more likely for the drivers and passengers feel unsafe and complain. However, there is lack of systematic analysis and research on the untypical NVH problem in the automotive industry. This paper systematically expounds the test and analysis process of abnormal noise. According to the correlation comparison between the full vehicle and the drivetrain subsystem platform, it is found that the differential assembly is the
Zhang, Jun, Chen, Yu
Simulating HVAC Noise in Vehicle Cabin with Material Absorption Modelling2022-01-03613/29/2022
Design of HVAC system plays an important role in acoustic comfort for passengers. With automotive world moving towards electrical vehicles where powertrain noise is low, designing low noise HVAC system is becoming more important. For an automobile manufacturer, ability to predict the production vehicle cabin noise at the early design stage is important as it allows more freedom for design changes, which can be incorporated in the vehicle at lower cost. Although HVAC prototype and system level testing at early design stage is possible for noise estimation but flow field is not visible in test that makes difficult to improve design. CFD simulation can provide detailed information on flow field, noise source strength and location. But in such a simulation, accurate prediction has been a challenge due to the inability of CFD tools to model acoustic absorptive characteristics of interior walls of cabin. This paper focusses on prediction of air borne noise of HVAC system inside a vehicle
Kandekar, Ambadas, Kakade, Abhishek, Duppati, Darshan, Luzzato, Charles, Mann, Adrien, Titave, Uttam
Bus NVH refinement: A Journey towards Comfortable Future2021-26-02729/22/2021
The future of bus transit in new millennium is promising. This optimism is based on an anticipated long-term slowdown in growth of suburbs and revitalization of central cities. It reflects and escalates the public concern with traffic congestion, sprawl and pollution. This calls for double the use of public transport to address above issues. It calls for changing the mind-set of society towards public transports like buses, coaches etc. This could happen if bus design ensures right comfort, safety & TCO by ensuring refined bus transport. Hence, it is responsibility of OEMs to provide the new generation buses and coaches, which will ensure the public demands of comforts in terms of NVH refinement. This paper covers the innovative approach used to convert the existing bus NVH refinement to next level as a short-term solution and with the intention of articulating NVH strategies for new generation bus development. This work explains combined experimental and simulation approach deployed
Doshi, Sohin, Taware, Girish, Kalsule, Dhanaji, Bijwe, Vilas, Naidu, Sudhakara
Design & Development of Partial Engine Encapsulation for Interior Noise Reduction in Commercial Vehicles2021-26-02839/22/2021
This paper focuses on partial encapsulation technique for reducing air-borne noise from the rocker cover of a commercial vehicle diesel engine. Due to increasing awareness, customers demand for improvised NVH-Noise Vibration and Harshness performance in modern day vehicles. Better NVH performance implies better comfort for passengers as well as vehicle operator. This further increases the driver up time due to reduced driver fatigue. In order to improve NVH performance of existing vehicle and observe different noise and vibration zones, detailed noise and vibration mapping was carried out on one of our vehicle platform. It is observed that engine noise is one of the major contributors for interior noise, apart from road inputs etc. There are well established methods to reduce the inherent noise of the engine, but the same might affect other performance parameters including fuel efficiency and exhaust emissions, which are pain areas of major automotive industries due to stringent
Jadhav, Sourabh, Saxena, Saahil
Inverse Reconstruction of the Spatial Distribution of Dynamic Tire-Road Contact Forces in Time Domain Using Impulse Response Matrix Deconvolution for Different Measurement Types2021-01-10618/31/2021
In tire development, the dynamic tire-road contact forces are an important indicator to assess structure-borne interior cabin noise. This type of noise is the dominant source in the frequency range from 50-450 Hz, especially when rolling with constant angular velocity on a rough road. The spatial force distribution is difficult or sometimes even impossible to simulate or measure in practice. So, the use of an inverse technique is proposed. This technique uses response measurements in combination with a digital twin simulation model to obtain the input forces in an inverse way. The responses and model properties are expressed in the time domain, since it is specifically aimed to trace back the impact locations from road surface texture indents on the tire. In order to do so, the transient responses of the travelling waves as a result of these impacts is used. The framework expresses responses as a convolution product of the unknown loads and impulse response measurements. Tikhonov
Devriendt, Harald, Naets, Frank, Kindt, Peter, Desmet, Wim
The Noise and Vibration Response of Eight Light Vehicles on Sinusoidal and Conventional Rumble Strips2021-01-11068/31/2021
Noise and vibration measurements were conducted on eight light vehicles ranging from small compact passenger cars to a large sport utility vehicle on and off shoulder rumble strips of two different designs to assess the input to a vehicle operator when the vehicle departed from the travel lane. The first design was a more conventional design, consisting of cylindrical indentions ground into the pavement at regular 30 cm intervals, and a continuous sinusoidal profile with a peak-to-peak length of 36 cm. Triaxial vibration measurements were made at six locations, including the steering wheel and column, the seat cushion and track, and the front and rear spindles. Interior noise was measured at six locations, one at the operator’s outward ear and five at the front seat passenger (three in the fore/aft locations of the seat and at outboard and inboard ear locations). In addition to the in/on vehicle measurements, pass-by noise levels were made. The measurements were performed at 97 km/h
Donavan, Paul R., Janello, Carrie
Real-Time Sound and Vibration Modelling for Electric Motor2021-01-10818/31/2021
The replacement of the ICE engine with an electric motor has led to a significant reduction in vibration and noise. The characteristics of the electric motor as part of the powertrain still need consideration from an NVH perspective, as there are still two highly tonal components generating noise to the cabin, albeit at higher frequencies. The radial electromagnetic force causes a structural vibration on the casing which changes with motor speed and can be used to indicate vehicle speed. The current excitation causes a primarily tangential force on the poles of the motor at a specific frequency, but both are narrow band and can cause annoyance. The traditional approach to predicting the sound radiation of electric motors is usually based on finite element analysis (FEA). While this method has the capability to estimate the time response, it is computationally too demanding and does not allow for early investigations at systems level. To obtain the real-time sound and vibration data
Gao, Boyang, O'Boy, Dan J., Mavros, George
Development of a Process to Predict Whole Vehicle Aeroacoustic Interior Noise2021-01-10478/31/2021
Quality and refinement are of paramount importance for luxury vehicles. The rapid electrification of the automotive industry has increased the contribution of aeroacoustics to the consumer perception of sound quality. The ability to predict whole vehicle aeroacoustic interior noise is essential in the development of vehicles with an extraordinary acoustic environment. This publication summarises the development of a process to combine lattice Boltzmann computational fluid dynamics simulations, with a whole vehicle statistical energy analysis model, to predict the aeroacoustic contribution from all relevant sources and paths. The ability to quantify the relative contribution of glazing panels and path modifications was also investigated. The whole vehicle aeroacoustic interior noise predictions developed, were found to be within 2dB(A) of comparable test vehicle wind tunnel measurements, across a broad frequency range (250-5000Hz). The ability to determine panel contributions and
West, Benjamin, Daniels, Holly, Venor, Joseph, Martin, Simon
Interior Floor Engineering: Acoustic vs. Compression Performance2021-01-11298/31/2021
The interior floor of a vehicle cabin occupies a significant amount of surface area in proportion to the cabin as a whole, and as such provides a prime opportunity for acoustic treatment. Generally speaking, floor materials must be relatively limp to achieve high acoustic performance. However, the tactile quality of a vehicle floor is very important. The end customer has an expectation for how it should feel to step onto the floor of a vehicle: a carpet should “give” slightly, but not compress fully, under pressure. A carpet that is too stiff or not stiff enough may be perceived as indicative of low quality. Thus, acoustic targets and stiffness targets tend to be at odds. A vehicle interior floor is a trim component which consists of different layers and which can have different pile-up configurations. Such a pile-up typically consists of a soft layer, called a decoupler, and a top layer. Previous work has shown how CAE tools can predict part-level compression behavior during design
Frey, Andrea, Koeske, Ben, Li, Wanlu, Wichmann, Brandon
Prediction and Validation of Cab Noise in Agricultural Equipment2021-01-10708/31/2021
To improve overall customer experience, it is imperative to minimize the noise levels inside agricultural equipment cab. Up-front prediction of acoustic performance in product development is critical to implement the noise control strategies optimally. This paper discusses the methodology used for virtual modeling of a cab on agricultural equipment for prediction of interior noise. The Statistical Energy Analysis (SEA) approach is suitable to predict high frequency interior noise and sound quality parameters such as articulation index and loudness. The cab SEA model is developed using a commercial software. The structural and acoustic excitations are measured through physical testing in various operating conditions. The interior noise levels predicted by the virtual model are compared with the operator ear noise levels measured in the test unit. The resultant SPL spectrum from SEA correlates well with the test. This model is used to optimize the noise control treatments and improve the
Mandke, Devendra, Fapal, Anand, Pawar, Sachin, Cone, Kerry
Subjective and Objective Seat Feature Acoustic and Vibration Response2021-01-10758/31/2021
Compressors, fans, and valves in seats used for occupant height adjust, lumbar, heating, and cooling can be objectionable if felt or heard. An approach to measure subjectively and objectively both vibration and noise experienced by a seated occupant will be described along with results, ranking, statistical significance, correlation, and suggestions for noise control. The objective portion included acoustic measurements through a binaural headset worn by each occupant and vibration measurements were recorded using a seat pad accelerometer disc at the buttocks and a source accelerometer. A subjective questionnaire with Likert, Borg, Magnitude Estimation, Semantical Differences, and Ranking based questions was obtained from 9 subjects. The transfer path the vibration energy takes to reach the receiver, vibration or acoustic, will be explored with transfer function measurements and a discussion of potential mitigation techniques: source mounting, encapsulation, and other design
Haylett, Jim, Romagosa, Francesc, Nelson, Erik
Interior Noise and Tactile Vibration Refinement of Commercial Vehicle Through Experimental Analysis2021-01-10738/31/2021
Noise & Vibration refinement of automotive vehicles is becoming important parameter due to its influence on environmental aspect and comfort perceived by occupants. NVH parameters are driving factors in current vehicle design strategy. Drivers comfort is extremely important, and driver’s expectations from commercial and heavy-duty trucks are as good as refined passenger cars. Other trends in commercial vehicle segment such as engine downsizing, weight, cost reduction and meeting stringent emission norms have influenced vehicle design dynamics. These parameters are critical and often contribute to vehicle NVH issues. Considering these new trends in commercial vehicle segment, it becomes challenging for an NVH engineer to provide optimized solutions. NVH issues could be related to the various subsystems such as driveline, axle, transmission steering wheel etc. in the vehicle and its resonant frequencies. In commercial vehicles, driveline design parameters, power train mounting system and
Sankpal, Kiran, Thakur, Sunil, Kunde, Sagar, Wagh, Sachin, Sharma, Vijay
Numerical Investigation of Tonal Noise at Automotive Side Mirrors Due to Aeroacoustic Feedback2020-01-15146/3/2020
In addition to the typical broadband noise character of wind noise, tonal noise phenomena can be much more disruptive, regardless of the overall interior noise quality of the vehicle. Whistling sounds usually occur by flow over sharp edges and resonant gaps, but can also be caused by the feedback of sound waves with laminar boundary layers or separation bubbles and the resulting frequency-selective growth of boundary layer instabilities. Such aeroacoustic feedback can e.g. occur at the side mirror of a vehicle and one compellingly needs the coupling of acoustic and flow field. A compressible large eddy simulation (LES) is in principle suitable but one has to take care of any numerical artifacts which can disturb the entire acoustic field. This paper describes the possibility to resolve aeroacoustic feedback with a commercial 2nd/3rd order finite volume CFD code. A zonal RANS/LES approach is used to ensure a realistic flow around the exterior side mirror mounted at a Mercedes-Benz C
Schell, Alexander, Eiselt, Mark
Road Noise Evaluation by Sound Quality Simulation Module2020-01-12754/14/2020
An objective evaluation of sound quality is a technical bridge connecting sound pressure level (SPL) and human auditory sensation. In this paper, an algorithm is proposed for calculating objective evaluation parameters of sound quality (including loudness, sharpness and articulation index), considering acoustic characteristics of human external ear, middle ear and inner ear to reflect auditory sensation. A sound quality simulation (SQS) module is coded according to the algorithm. The module is used for evaluating sound quality of road noise from an SUV in three steps. Firstly, interior noise is predicted by integrating finite-element method (FEM), hybrid FE-SEA method, and statistical energy analysis (SEA) for low frequency (20~315 Hz), medium frequency (315~500 Hz), and high frequency (>500 Hz) in 1/3 octave band, respectively. The predicted interior noise SPLs are compared with the measured results, with deviations less than 3dB in average. Secondly, the sound quality parameters are
Gu, Perry, Mao, Jie, Chen, Zhidong, Ding, Zhi, Cheng, Lei, Zhu, Zhenying, Peng, Hong
A Case Study on Reducing the Fuel Pulse Noise from Gasoline Engine Injectors2020-01-12764/14/2020
There are many noise sources from the vehicle fuel system to generate noise inside a vehicle. Among them, the pressure pulsation due to the rapid opening and closing of gasoline engine injectors can cause undesirable fuel pulse noise. As the pressure pulsation propagates in the fuel supply line toward to rear end of the vehicle, the pressure energy is transferred from fuel lines to the vehicle underbody through clips and into the passenger compartment. It is crucial to attenuate the pressure pulsation inside the fuel line to reduce the fuel pulse noise. In this paper, a case study on developing an effective countermeasure to reduce the objectionable fuel pulse noise of a V8 gasoline injection system at engine idle condition is presented. First, the interior noise of a prototype vehicle was tested and the objectionable fuel pulse noise is exhibited. The problem frequency ranges of the pulse noise were identified. In order to find the countermeasures to reduce the pulse noise, several
Zhang, Weiguo, Tan, Toon, Malicki, John, Whitehead, Glenn
Vibrational Analysis Method on High-frequency Electric-drive Motor Noise2020-01-04634/14/2020
When a vehicle is cruising, unpleasant noise in the 4 to 5 KHz high-frequency band can be heard at the center of all seats in the vehicle cabin. In order to specify the source of this noise, the correlation between the noise and airborne noise from the outer surface of the transmission was determined, and transfer path analysis was conducted for the interior of the transmission. The results indicated that the source of the noise was the 0th-order breathing mode specific to the drive motor. To make it possible to predict this at the desk, a vibrational analysis method was proposed for drive motors made up of laminated electrical steel sheets and segment-type coils. Material properties data for the electrical steel sheets and coils was employed in the drive motor vibrational analysis model without change. The shapes of the laminated electrical steel sheets and coils were also accurately modeled. The status of minute slippage between the laminated layers and contact between the electrical
Saito, Toshihiro, Miyamoto, Koji
The Resolution of 8th Order Whining Noise for a Battery Electric Vehicle2020-01-12694/14/2020
With significant improvement in overall vehicle NVH performance in recent years, sound quality has increasingly become an important customer concern. In search of excellence in customer satisfaction with BEVs (Battery Electric Vehicles), optimizing e-motor noise is one of the most effective ways to improve the vehicle sound quality. This paper aims to resolve a whining noise issue from a PMSM (Permanent Magnet Synchronous Motor) during the development of a BEV program. The most critical order of the whining noise from an e-motor on market today is most likely the 48th order, which could be mitigated by implementing sound package material on the motor casing. In this work, however, the 8th order instead is found to be the most critical issue, and it is perceived as the whining noise in the frequency range under 600Hz. With such a low frequency content, sound package treatment has little effect. With subjective evaluation and test data analysis, it is found that the worst case is
Feng, Jingting, Deng, Jianjiao, Liu, Yingjie, Hou, Hangsheng, Oka, Ryusuke
Acoustic performance analysis of automotive HVAC duct designs using a Lattice-Boltzmann based method and correlation with Semi-anechoic chamber.2020-01-12634/14/2020
Acoustic comfort of automotive cabins has progressively become one of the key attributes of vehicle design, with wind noise and HVAC noise being two of the key contributors to noise levels heard inside the car. With the increasing prevalence of hybrid technologies and electrification and the associated reduction in powertrain noise levels, the industry has seen an increasing focus on understanding HVAC noise, as it is a main source of noise in the cabin if not the single one when the vehicle is stopped. The complex turbulent flow path through the ducts, combined with acoustic resonances can potentially lead to significant noise generation, both broadband and tonal. In order to avoid time consuming and expensive late stage design changes, or avoid being hit by low consumer rating ignoring the issues, it is important to identify potential problems early in the design process and take appropriate measures to rectify them. In this study, the noise characteristics of three HVAC duct designs
Pasupuleti, Sivaji, Horne, Kevin, Beedy, Jeremy, Guzman, Arturo, Doroudian, Mark, Sivakumar, Prasad, Mann, Adrien, Kim, Minsuk
Applications of Strain Measurements to Improve Results on Transfer Path Analysis2019-36-03231/13/2020
Vehicles with lower noise levels and better levels of vibratory comfort for passengers made the area of noise, vibration and harshness (NVH) one of the main areas related to the perception of vehicle quality. Several approaches on the contribution of transfer paths have been studied to define the propagation energy in vehicular structures. Transfer Path Analysis (TPA) is a tool to improve NVH performance with the primary goal of reducing and improving perceived vibrations and noise in the cabin vehicle by occupants. Indirect methods are especially important in cases where the force signals are immeasurable in practice in terms of cost and space for sensor couplings, in the measurement configuration, and particularly in the case of distributed forces. The matrix inversion method, perhaps the most popular classic TPA, identifies operational forces using passive body acceleration. However, removal of the source can change the dynamic characteristics of the assembled structure and increase
Ramos, A. C. R., Melo, C. A. P., Álvarez-Briceño, R., de Oliveira, L.P.R
Technique for Front-loading Countermeasures against Deterioration of Sound Quality in Vehicle Interior due to Rapid Combustion in an SI Engine2019-01-230412/19/2019
This paper discusses a technique for the examination of countermeasures at the design stage of the prototype vehicle in order to realize efficient enhancement of the engine combustion noise quality in the vehicle interior. An existing sound quality evaluation method was applied as a simulation technology. The deterioration of the sound quality of combustion noise in the passenger compartment of a new vehicle was estimated from the in-cylinder pressures of a newly developed engine measured on a dynamometer test bench and the structural response functions obtained from the previous mass production vehicle. In addition, the level of reduction in structural response sensitivity necessary for the enhancement of combustion noise quality was estimated for each frequency band. Based on the results, effective countermeasures for the enhancement of combustion noise quality were selected and reflected in the drawings for the initial prototype vehicle. This made it possible to realize the target
Torii, Kenji, Tsuruta, Tatsunori
GKN spreads premium propshaft tech to quiet pickup cabins19AUTP10_1110/1/2019
It may seem a long way in engineering and NVH terms from premium European cars such as Audi's A5 and A7 to light duty trucks, but GKN Automotive has bridged that gap with its latest lightweight all-wheel drive (AWD) modular propshaft. Many pickups suffer a significant amount of unwanted NVH emanating from the front propshaft, with its two universal or CV joints and an interconnecting shaft positioned below and close to the passenger cabin. But now GKN Automotive has “re-characterized” its premium car driveline system to an entirely different vehicle category. “With a traditional truck front propshaft, the level of noise entering the cabin is perceived as a drone,” explained Michael Miller, GKN's propshaft product technology manager. “We've worked on applications of our new technology where the cabin NVH levels have been dramatically reduced. Positive results stem from the combination of joints used in our lightweight modular front propshaft.”
Birch, Stuart
Application of Multi-Attribute Weighted Gray Target Decision in Automobile Noise Reduction Scheme Evaluation02-12-03-00147/3/2019
In the selection of automobile noise reduction schemes, the lack of comprehensive quantitative index system and objective evaluation method is a serious problem. In this article, the methods of analytic hierarchy process (AHP) and gray target decision were used to solve the problem. Firstly, AHP and gray target decision method were introduced respectively in detail. Secondly, three automobile noise reduction schemes were illustrated. Four types of data were selected as the decision indexes, and the weight coefficients of all the decision indexes were calculated using the AHP. Then multi-attribute mixed weighted gray target decision model was established. The optimum scheme was obtained by the calculation of the off-target distance and the sorting of the calculation results. The proposed method can quantify the evaluation process and overcome the disadvantages of the traditional analogy method. The example shows that the method is feasible.
Zhao, Zhendong
Tonal Annoyance Metric Development for Automotive Electric Vehicles2019-01-14676/5/2019
Historical metrics intended to drive the development of vehicle powertrains have focused on sounds that are characteristic of IC engines. The interior noise contribution of the propulsion system in electric vehicles has significantly more tonal noise (and much less impulsive and broadband noise) than their IC engine counterparts. This tonal noise is not adequately represented by current propulsion systems metrics. While metrics exist today that were developed to represent the presence of tones in sounds most have focused on the level aspect of the tones relative to the surrounding noise or masking level, some examples include tonality, tone-to-noise ratio, and prominence ratio. A secondary, but also important aspect of tones is the annoyance as a function of frequency. This paper will highlight the development of a tonal annoyance weighting curve that can be used to account for the frequency aspect of tonal annoyance relative to electric vehicles. This weighting curve can then be used
Pietila, Glenn, Seldon, William, Roggenkamp, Timothy, Bohn, Timothy
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