Browse Topic: Noise

Items (5,944)

Optimisation of Rotor Skewing of a Yokeless And Segmented Armature Axial Flux Machine

2025-01-0311To be published on 07/02/2025

This paper presents an optimization of rotor skewing of an Axial Flux Machine (AFM) in a Yokeless And Segmented Armature (YASA) design in the torque-speed characteristics diagram. AFM have advantages regarding a compact design and high torque density compared to other variants of permanent magnet machines. The drive train Noise, Vibration and Harshness (NVH) performance is influenced by cogging torque, magnetic torque ripple and tooth forces. While the axial skewing of rotors in radial flux machines (RFM) has already been extensively studied to minimize these magnetic excitations, this represents a target value for optimizations in AFM. Optimizations are carried out and validated using 2D and 3D finite-element (FE) models. The 2D model combines multiple 2D slices but lacks accuracy because an insufficient inclusion of 3D effects. The 3D model allows to obtain a noticeable reduction by more than 30% of the dominant torque harmonic amplitudes over the whole torque-speed range in

Müller, Karsten, Maisch, Hannes, De Gersem, Herbert, Burkhardt, Yves

Noise Management in Electric Vehicle Compressors for Superior Cabin Comfort

2025-01-0191To be published on 06/16/2025

“This research addresses the issue of noise, vibration, and harshness (NVH) in electric buses, which can hinder their widespread adoption despite their environmental benefits. With the absence of traditional engines, NVH control in electric vehicles focuses on auxiliary components like the air compressor. In this study, the air compressor was identified as a major source of vibration, causing harsh contact between its oil sump and mounting bracket. Analyzing the vibrations revealed that the sump and bracket were not moving freely, increasing noise. Modifying the bracket design to allow more movement between the components successfully reduced both noise and vibration. The paper details the experimental process, findings, and structural damping methods to mitigate NVH in electric buses”.

Paroche, Sonu, Patel, Shubhanshi, Patidar, Ashok Kumar

NVH Improvement of Transmission Electric Oil Pump with Uneven Pitch Control

2025-01-0252To be published on 06/16/2025

Acoustic noise and vibration are always main issues to overcome in electric oil pumps for gearboxes in HEV and BEV. This paper introduces a noise reduction control method of electric oil pump in wet-type dual clutch transmissions. This paper proposes an uneven pitch control for electric oil pumps. For the noise reduction of vane pumps, mechanical arrangements of uneven pitch vain angle are widely used. However, the tooth angle of gear-type pumps should be even mechanically. The proposed uneven pitch control provides similar effects of the mechanical uneven pitch arrangement by instantaneous motor torque controls of the electric oil pump which cannot have uneven pitch mechanically. The magnitude of motor torque for each pump tooth is determined by an uneven pitch formula which is widely used for mechanical vane pumps in previous study and patents. A formula for the shape of motor torque is proposed by analyzing pressure fluctuations of pump as a combination of trigonometric and

Choi, Chinchul, Kim, Jongbeom

Numerical Simulation and Parametric Optimization of Engine/Powertrain Mounts: Identifying Key Design Variables to Reduce NVH Noise

2025-01-0251To be published on 06/16/2025

Abstract: Introduction: Engine and powertrain mounts are vital for isolating vibrations and reducing the transmission of Noise, Vibration, and Harshness (NVH) from the engine to the vehicle structure. Despite technological advancements, addressing NVH issues related to tribological factors continues to pose significant challenges in automotive engineering. Aim: This study aims to systematically identify and optimize design parameters of engine/powertrain mounts to minimize NVH levels using CAE tools and parametric optimization techniques in Abaqus and Isight, respectively. Purpose: The purpose of this research is to investigate the correlation between various design parameters of powertrain mounts and their impact on NVH characteristics. Specific attention is focused on noises such as clunking, banging, or thumping that emerge from the engine bay under dynamic conditions like acceleration, braking, or turning. These sounds often occur as the engine moves excessively due to worn mounts

Ganesan, Karthikeyan

Metamaterial application to automotive glass for vibration reduction and reduced noise transmission

2025-01-0119To be published on 05/05/2025

A metamaterial which, attached to the edge of a panel, reduces vibration results in reduced noise transmission into a vehicle. In this particular case, the metamaterial is designed to be attached to the edge of a glass panel and can reduce panel vibration and noise transmission due to wind or other sources into the vehicle interior. Acoustic transmission loss and panel vibration assessments show the benefit of this approach.

Sorenson, Steve, Li, Xiaopeng, Moore, Jaime, Robison, Scott

Tire simulation to optimize road noise

2025-01-0111To be published on 05/05/2025

Tires have a significant impact on vehicle road noise. In the past, tire development has been driven by testing that is costly and time-consuming. Simulation approaches are becoming more important as the need for NVH performance requirements rises and vehicle development cycles get shorter. Therefore, simulation techniques should be used to tires at an early stage. Among various road noise, the noise of 80~160 Hz is easily felt when driving on the rough road, and this noise has a great relationship with the tire structural design. How to improve the road noise problem through tire simulation has become an important issue, so this paper puts forward the concept of virtual tire design and clarifies the responsibility of automotive enterprises and tire suppliers. In virtual tire design or tuning, an appropriate tire model is crucial for road noise performance. The CDtire model can meet the requirements, so in this article, CDtire is used to improve road noise at 80-120Hz. To obtain an

Zhang, Ben, Yu Sr, Jing, Chen, Qimiao, Liu, Xianchen, Gu, Perry

NVH Improvement of BEV transmission using housing modal analysis co-relation and design optimization

2025-01-0106To be published on 05/05/2025

Battery Electric Vehicles (BEVs) are extremely sensitive in terms of NVH requirements. While the engine is being replaced with an almost silent electric motor, the transmission noise appears persistent and demands more silent transmission. This has raised demand for improvement in design as well as manufacturing quality. Various innovations are being made to drive an improvement in the NVH. The following paper will discuss the improvement in NVH achieved through a design optimization of the housing using modal analysis. Firstly, the NVH results were co-related with the modal analysis and the cause for the dominant peak in amplitude of the NVH graph associated with the housing modes were mapped. A simple Excel based correlation matrix is used to map the list of all Eigenfrequencies of housing and its corresponding gear tooth frequency. Further optimization is done in housing design to defer the modal frequencies and another NVH test was run. It was proven that housing design

Pingale, Abhijeet Satish, Deshpande, Prasannakumar

Feasibility of In-Situ Vehicle-Level Sound Transmission Loss Measurement to Guide Dash Pass-Through Grommet Selection

2025-01-0122To be published on 05/05/2025

Noise transmission through the vehicle dash panel plays a critical role in isolating passengers from noise sources within the motor bay of the vehicle. Grommets that contain electrical harness routing as well as HVAC lines are examples of dash panel pass-throughs that should be selected with care. Acoustic performance of these components is generally characterized in terms of measured quantities such as noise reduction (NR), sound transmission loss (STL), and insertion loss (IL). These measurements need to be carried out per SAE or ASTM standards in appropriate anechoic or reverberant chambers as this is important for consistency. This work explores an in-situ measurement of the grommet STL performance in the vehicle environment. It utilizes a repurposed vehicle with its cabin retrofitted to serve as an anechoic chamber and its frunk acting as a reverberant chamber. Results of this in-situ measurement are then compared to measurements following industry standards to discuss the

Joodi, Benjamin, Jayakumar, Vignesh, Chang, Michael, Geissler, Christian, Pilz, Fernando, Conklin, Chris

Hybrid 3D Sound Intensity and Simulation for Optimizing Acoustic Output of Truck Rear Axles

2025-01-0105To be published on 05/05/2025

This study presents a novel methodology for optimizing the acoustic performance of rotating machinery by combining scattered 3D sound intensity data with numerical simulations, focusing on the rear axle of a truck. Using Scan&Paint 3D, sound intensity data is rapidly acquired over a large spatial area with the assistance of a 3D sound intensity probe and infrared stereo camera. The experimental data is then integrated into far-field radiation simulations, enabling detailed analysis of the acoustic behavior and accurate predictions of far-field sound radiation. This hybrid approach offers a significant advantage for assessing complex acoustic sources, allowing for quick and reliable evaluation of noise mitigation solutions. While the current application focuses on the truck's rear axle far-field radiation, the same method can be extended to predict in-cabin sound pressure, providing a versatile solution for many industrial problems.

Fernandez Comesana, Daniel, Vael, Georges, Robin, Xavier, Orselli, Joseph, Schmal, Jared

NVH improvement of the BEV transmission by altering bearing mounting arrangement.

2025-01-0104To be published on 05/05/2025

As per metaphor, “The squeaky wheel gets the grease” the transmission of battery electric vehicle (BEVs) gets topmost attention in terms of NVH improvement. While the engine is getting replaced with an almost silent electric motor, the transmission noise appears persistent and demands more silent transmission. This has raised demand for improvement in design as well as manufacturing quality. Various innovations are being done to drive an improvement in the NVH. Following paper will discuss the improvement in NVH achieved through a design innovation in the way bearings are installed and demonstrated a significant amount of improvement. We have used SMT MASTA used as a simulation tool to predict the expected results and a Transmission Dyno test bench in an anechoic chamber to test the NVH performance on physical sample. The innovation was done on a small single speed two stage reduction gearbox coupled with a 100 NM, 14000 RPM battery electric motor. Though the bearings have

Pingale, Abhijeet, Soni, Jaldeep

Virtual Gear Noise Analysis and Case Design Investigation for Concept Parallel Axis Drive Unit

2025-01-0102To be published on 05/05/2025

For electric vehicles, it is critical to develop drive units that produce a minimal amount of noise while meeting efficiency needs for a given application. Modern computational resources and accumulated experience allow for engineers to evaluate gear noise early in the development process and influence the design of the drive unit. This paper documents a high-fidelity virtual engineering approach to evaluate gear noise in a concept parallel axis drive unit and provide learnings to influence design of the external structure to improve NVH performance. By using the latest simulation tools to calculate and visualize the noise and vibration characteristics of the drive unit, designers and developers can implement design changes in optimization iterations to reduce noise and vibration. Gear harmonic response is firstly analyzed through a system model which considers structural deflection and misalignment, then a FE housing model is incorporated which is used for noise radiation evaluation

Lima, Luiz, Shi, Zhenghong, Xu, Hai, Reynolds, Craig, Miller, John

Excavator exterior noise contribution analysis using angle-based operational acoustic load synthesis.

2025-01-0062To be published on 05/05/2025

Since earth moving machines (EMM) are subject to exterior noise (EN) regulations, OEMs need to develop mitigation solutions from an early design stage. It is challenging to predict solution effectiveness at early design stage. Excavators are distinct compared to other EMM as their upper frame rotate while keeping lower frame fixed. ISO 6395(2) or EC/2000/14(1) require EMMs to follow specific operating maneuvers where noise sources change their position, directivity, and speed along the operating cycle. These conditions pose challenges in performing noise contribution analysis as a function of angular position and operating condition. Authors successfully demonstrated Acoustic source quantification and contribution analysis for linearly moving EMMs. However, excavator pose data processing challenges due to angular motion. This work demonstrates the use of frequency domain ASQ for operational acoustic source quantification and use of frequency domain virtual prototype sub structuring

Vesikar, Prasad Balkrishna, Chaduvula, Prasanna, Aquino Arriaga, Adrian Antonio, Haynes, Timothy, Drabison II, John

Application of Hybrid SEA in Vehicle NV Package Optimization

2025-01-0050To be published on 05/05/2025

As India’s economy expands and road infrastructure improves, the number of car owners are expected to grow substantially in the coming years. This market potential has intensified competition among original equipment manufacturers (OEMs) to position their products with a focus on cost efficiency while delivering a premium user experience. Noise and Vibration (NV) performance is a critical differentiator in conveying a vehicle's premiumness, and as such, NV engineers must strategically balance the achievement of optimal acoustic performance with constraints on cost, mass, and development timelines. Traditionally, NV package optimization occurs at the prototype or advanced prototype stage, relying heavily on physical testing, which increases both cost and time to market. Furthermore, late-stage design changes amplify these challenges. To address these issues, this paper proposes the integration of Hybrid Statistical Energy Analysis (HSEA) into the early stages of vehicle development

Rai, Nitesh, Mehta, Makrand, Ravindran, Mugundaram

Characterize the Sound Field Generated from a Vehicle Horn by Pellicular Analysis

2025-01-0058To be published on 05/05/2025

To predict the sound field produced by a vehicle horn requires a good source representation of it in the full vehicle model. This paper investigates the characterization of a physical vehicle horn by an inverse method called pellicular analysis. To implement this method, firstly an acoustic testing is performed to measure the sound pressure radiated from the horn at a certain number of microphone locations in a free field environment. Based on the geometry of a virtual horn, the locations of each microphone and measured sound pressure data, pellicular analysis is adopted to recover a set of vibration pattern of the virtual horn. The virtual horn and the recovered vibration information are then incorporated in a full vehicle numerical model to simulate its exterior sound field. The validity of this approach is confirmed by comparing the prediction for a horn in a production vehicle to the corresponding physical test which is required to meet the Brazilian regulation CONTRAN 764/2018.

Yang, Wenlong, Melo, Andre

A review on Electric Vehicle NVH challenges and recent trends

2025-01-0042To be published on 05/05/2025

Electric vehicles (EVs) present a distinct set of challenges in noise, vibration, and harshness (NVH) compared to traditional internal combustion engine (ICE) vehicles. As EVs operate with significantly reduced engine noise, other sources of noise, such as motor whine, power electronics, and road and wind noise, become more noticeable. This review paper explores the key NVH issues faced by EVs, including high-frequency tonal noise from electric motors, gear meshing, and vibrations. Additionally, it examines recent advancements and trends in NVH mitigation techniques, such as active noise control, improved material insulation, and advanced vibration isolation systems. Furthermore, this paper discusses the role of computational tools, simulation technologies, and testing methodologies in predicting and addressing NVH concerns in EVs. By providing an in-depth analysis of the challenges and the latest innovations, this review aims to contribute to the ongoing development of quieter and

Hazra, Sandip, Khan, Arkadip Amitava

Flow-Induced Noise Prediction and Validation of a Heavy-Duty Electric Vehicle's HVAC System Using the Lattice Boltzmann Method

2025-01-0057To be published on 05/05/2025

Within automobiles, the HVAC is a critical system to regulate the occupants’ thermal comfort. However, at its high operating speeds, it can contribute significantly to the overall sound levels perceived by the cabin occupants, impacting their experience. This is especially true in the case of electric vehicles due to their overall quieter operation. This work has the intention to validate HVAC noise predictions using computational fluid dynamics (CFD) simulations. In addition, CFD simulations provide detailed flow field insights which are essential to identify and rank the main noise sources, and it ultimately allows a better understanding of the physical mechanisms of noise generation on similar systems. These insights are very difficult, if not impossible, to obtain with physical testing and are key to designing a quiet and efficient HVAC system. Sound levels were measured experimentally at eight different locations inside of a Class-8 Nikola TRE hydrogen fuel cell electric semi

Ihi, Rafael, Fougere, Nicolas, Passador, Stephen, Woo, Sangbeom, Kim, James, Desouky, Mohamed

Subjective Development of EV Propulsion Noise to Drive Product Differentiation

2025-01-0067To be published on 05/05/2025

The frequency and amplitude content of powertrain noise is motor torque and speed dependent and tends to influence the driver’s subjective perception of the vehicle. This provides manufacturers with an opportunity to drive product differentiation through consideration of powertrain noise in early stages of the development cycles for electric vehicles (EVs). This paper focuses on the evaluation of customer preference and perception of acoustic feedback from different powertrain design options based on targeted powertrain orders and expected wind and road masking during high acceleration maneuvers. A jury study is used to explore customer feedback to a two-stage gearbox design with AC permanent magnet motor order combinations. The subjective influence of order spacing, dominant frequency content and the number of audible orders is studied to understand aural perspective product differentiation opportunities.

Joodi, Benjamin, Jayakumar, Vignesh, Conklin, Chris, Pilz, Fernando, Iyengar, Shashank, Weilnau, Kelby, Hodgkins, Jeffrey

Comprehensive Analysis and Optimization of Door Closing Sound Quality of a Heavy Truck

2025-01-0066To be published on 05/05/2025

Based on the objective and subjective experiment and finite element analysis, the influencing factors on the door closing sound quality of a heavy-duty truck is analyzed and optimized. Results show that the loudness and sharpness can be reduced apparently by increasing stiffness and damping of the door. The sound quality can be enhanced by increasing the pressure release area, which can decrease the air resistance of dooring closing. By adding holes on the inner liner and changing the pressure release location, the dooring closing air resistance is reduced from 289 Pa to 181 Pa. In terms of the rebound sound, the sound level is positively relative to the door closing force. Increasing the protrusion height and decreasing the stiffness of the vibration absorber of the handle can improve the rebound sound quality. Optimizing the absorbers on both ends and adding damping material can decrease the loudness by 47.8%, reduce the cavity sound, dismiss the trembling and improve the compact

Wang, Jian, Zhang, Yongshen, Feng, Lei, Xie, Chenhao, Lin, Jiewei, Sun, Changchun

Active Control of Engine Order Noise for Heavy-duty Trucks: Using the Genetic Algorithm for the Optimization of Error Microphone Arrangement

2025-01-0013To be published on 05/05/2025

The arrangement of error microphones for a vehicle active noise control (ANC) system is no trivial work, especially for heavy-duty trucks due to the dilemma resulted from the large volume of the cab and the limited number of microphones accepted by most manufacturers in the auto industry. Most ANC developers resort to trial and error, which is not only a heavy workload given the amount of interested working conditions to be test, but also does not guarantee to yield the optimum noise cancellation performance. In this paper, the authors proposed an error microphone selection methodology using a genetic-algorithm (GA) -based mechanism. The target vehicle was a heavy-duty truck with a six-piston diesel engine, and two scenarios were particularly interested, i.e. driver & copilot and driver & one passenger sleeping on the berth. We first arranged eight microphones at different locations in the cab, five on the headrests, two on the B pillars and one at the head position of the sleeping

Wang, Jian, Ling, Zihong, Zhang, Zhe, Cai, DeHua, lv, Xiao, Zhang, Ming, Gao, GuoRan

Plug-in hybrid and range extender NVH – Challenges and Solutions

2025-01-0101To be published on 05/05/2025

The automotive industry continues to develop new powertrain and vehicle technologies aimed at reducing overall vehicle-level fuel consumption. While the use of electrified propulsion systems is expected to play an increasingly important role in helping OEM’s meet fleet CO2 reduction targets, hybridized propulsion solutions can play a vital role in the electrification strategy of vehicle manufacturers. Plug-in hybrid and range extender vehicles show unique NVH challenges due to their different possible operation modes. First, the paper outlines different driveline architectures for PHEV and range extenders. Given the multiple general architectures, as well as operation modes which typically occur for these vehicles, characterizations and source-path analysis of these vehicles can be more complicated than conventional vehicles. In the following steps, typical NVH related challenges are highlighted and potential solutions for NVH optimization are discussed. While the overall noise levels

Wellmann, Thomas, Ford, Alex, Pruetz, Jeffrey

Simulation of Pass-by Fan Noise Emissions and Advancing Test Regulations for Heavy-Duty Electric Vehicles

2025-01-0086To be published on 05/05/2025

The rapid adoption of electric vehicles (EVs) necessitates updates to the automotive testing standards, particularly for noise emission. This paper examines the vehicle-level noise emission testing of a Nikola Class 8 hydrogen fuel cell electric semi-truck and the component-level noise emission testing needed to create a predictive simulation model using Wave6 software. The physical, component-level noise emission testing focused on individual cooling fans in a semi-anechoic chamber to assess their isolated noise contributions. With this data, an initial model was developed using spatial gradient statistical energy analysis, which successfully predicted pass-by noise levels based on varying fan locations and speeds. Real-world pass-by testing confirmed the model's accuracy across different cooling fan speeds. By leveraging advanced simulation techniques, engineers aim to enhance the accuracy and reliability of pass-by noise predictions through cost-effective studies of architectural

Passador, Stephen, Woo, Sangbeom, Liu, Ting-Wei, De La Vega Alonso, Gerardo, Kim, James

Localisation of Ultra-short Sound Emissions from Automotive Components by Using the Sound Field Scanning Method

2025-01-0092To be published on 05/05/2025

Design verification and quality control of automotive components require the analysis of the source location of ultra-short sound events, for instance the engaging event of an electromechanical clutch or the clicking noise of the aluminium frame of a passenger car seat under vibration. State-of-the-art acoustic cameras allow for a frame rate of about 100 acoustic images per second. Considering that most of the sound events introduced above can be far less than 10ms, an acoustic image generated at this rate resembles an hard-to-interpret overlay of multiple sources on the structure under test along with reflections from the surrounding test environment. This contribution introduces a novel method for visualizing impulse-like sound emissions from automotive components at 10x the frame rate of traditional acoustic cameras. A time resolution of less than 1ms eventually allows for the true localization of the initial and subsequent sound events as well as a clear separation of direct from

Rittenschober, Thomas

Do EVs Snore?

2025-01-0074To be published on 05/05/2025

As EV and PHEV adoption continues to increase more people will have direct experiences with these quieter vehicles in their daily lives. Topics such as 'propulsion sound' via Active Sound Design (ASD) and bystander safety through Acoustic Vehicle Alerting Systems (AVAS) have been discussed widely for many, many years...but who is talking about Charging Noise? Charging noise is a less spoken about topic because most EV / PHEV owners will charge their vehicles at their home, in their garage or their driveway, overnight when they are sleeping. Because of that people do not think much about charging noise. But anyone who has plugged in their car overnight will tell you a strange cacophony of sounds come from the car...and some can be downright concerning. In this paper data from several production EVs were measured during their normal charging cycle. Binaural recordings made inside and outside the vehicle are analyzed using psychoacoustics metrics to see what sounds would cause the most

Marroquin, Marc, Bray, Wade

Fast noise prediction of an electric powertrain integrated in various vehicles

2025-01-0076To be published on 05/05/2025

The automotive industry's transition to electrification raises new challenges to maintain a comfortable acoustics environment both inside and outside the car. This paper presents an innovative way to make an early prediction of the overall sound of a vehicle at driver’s ear by mixing noise sources that can be simulated and noise sources that can be measured at component level. This hybrid approach combining Test and Simulation data helps make decisions in the early design phase by predicting the noise of one component integrated in the whole vehicle. For instance, Valeo, with the help of sound synthesis techniques, is able to predict the sound of an e-drive when it is combined with Rolling noise that varies depending on the vehicle speed and the car segments - more or less refined, from a dataset of multiple vehicles. Realistic signals could be generated and compared with actual acoustic measurement to validate the method.

Redon, Milan, Dendievel, Clement, Pluton, Matthias

Electric compressor integration noise influence in Battery Electric Vehicles

2025-01-0075To be published on 05/05/2025

Within the automotive industry’s shift to Battery Electric Vehicles, in order to meet the global zero emission target, thermal management systems are key aspects to address. For instance, vehicle cooling requirements are reinforced to take into account the cabin comfort as well as battery management performances. Consequently to the increased cooling requirements, the critical component that is the Electric Drive Compressor, must operate at higher speeds and refrigerant pressures to achieve these targets. This trend results in increased noise levels which might occur inside the car cabin and outside. In this paper, noise investigations were performed on different Battery Electric Vehicles to assess the behavior of the electric compressor within a temperature controlled environment. Then, the electric compressors alone were investigated on specific test benches with compressor load units. The vehicle level assessment highlighted significant noise differences between vehicles. Further

Bennouna, Saad, Yamayoshi, Itsukyo, Del Valle, Edward

Snap-fits evaluation for minimizing the Squeak & Rattle in Automotives

2025-01-0091To be published on 05/05/2025

The world of plastic products has been growing due to its versatile properties, which have become an intrinsic and fundamental part of the engineering of new products. The most important aspects contributing to this spectacular growth are the design and assembly, making sure that plastic parts are designed optimally. The safety requirements have been increased due to the safety ratings and thus interior parts must provide more absorption and protection to occupants. The main connection types used in the plastic parts are heat stakes and snap fits. The purpose of a good snap fit is not only to have a high retention effort but also to present ergonomic characteristics with low insertion and extraction effort because each part requires a different function. With the time-dependent loading the material will redistribute its internal energy thereby performing a time-related flow leading to reduced pretension thus decreasing stiffness. This paper presents an analytical and numerical method

Michael Stephan, Navin Estac Raja, C M, Mithun, Mohammed, Riyazuddin, R, Prasath

Horn sound digital validation for ECE-R28 regulation compliance

2025-01-0008To be published on 05/05/2025

Every vehicle has to be certified by the concerned governing authority that it matches certain specified criteria laid out by the government for all vehicles made or imported into that country. Horn is one of the components that is tested for its function and sound level before a vehicle is approved for production and sale. Horn, which is an audible warning device, is used to warn others about the vehicle’s approach or presence or to call attention to some hazard. The vehicle horn must comply with the ECE-R28 regulation in the European market. Digital simulation of the horn is performed to validate the ECE-R28 regulation. In order to perform this, a finite element model of a cut model of a vehicle, which includes the horns and other components, is created. Fluid-structure coupled numerical estimation of the sound pressure level of the horn, with the appropriate boundary conditions, is performed at the desired location as per the ECE-R28 regulation. The simulation results thus obtained

Ramachandran, Balachandar, Raveendran, Roshin, Mondal, Arghya

Leveraging user feedback to optimize the tuning of EVSE models

2025-01-0020To be published on 05/05/2025

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

Correlated Beamforming Based on Deconvolution Methods for Identified Vehicle Exterior Wind Noise Sources and Interior Noise

2025-01-0025To be published on 05/05/2025

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, Blumrich, Reinhard, Wiedemann, Jochen

Design of a Reactive-Style Muffler for a Formula SAE Race Car

2025-01-0024To be published on 05/05/2025

The noise generated by internal combustion engines, particularly in high-performance vehicles like Formula SAE race cars, presents a significant challenge in adhering to strict competition noise regulations. To address this issue, mufflers are essential for reducing acoustic emissions. This study focuses on the design, manufacturability, optimization, and validation of a reactive-style muffler specifically for a Formula SAE combustion competition car. The proposed muffler utilizes two chambers to generate destructive interference, targeting the two dominant exhaust frequencies of the Honda CBR600RR engine to maximize transmission loss and reduce noise levels below the SAE-mandated range of 103–110 dB(C). A 3D model of the muffler was developed using SolidWorks, capturing the precise geometries required for acoustic optimization. The exhaust noise and muffler performance were simulated using GT-Suite, allowing for an evaluation of noise attenuation across engine speeds. Experimental

Labao, Kai, Middleton, Nicholas, Nuszkowski, John

HV-Battery Impact on Car Body Acoustics and Damping Package Case Study of the Electric Vehicle

2025-01-0041To be published on 05/05/2025

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

Directivity driven simulation methodology for efficient Acoustic Encapsulation

2025-01-0048To be published on 05/05/2025

Noise Reduction at the source level is critical to achieve the overall vehicle level interior targets. This method presents a novel approach that integrates directivity analysis with simulation techniques to optimize acoustic encapsulation design for automotive sound sources to achieve the targeted radiation levels. The foundation for this methodology is to measure the angular distribution of sound pressure levels around the noise source so called Directivity, at every frequency of interest and determine the most effective Acoustic encapsulation to achieve the targeted sound radiation. Accurate measurement of directivity in physical testing with fine angular resolutions can be complex and expensive, this study utilizes numerical simulation techniques using FEA to mitigate the challenges in mid frequency range. The scope of the study is focused on mid frequency sound pressure levels between 500-2000 Hz, which are determined to be significant contributors to overall DU noise. The first

Kaluvakota, Srikanth, Ghaisas, Nikhil, Pilz, Fernando

Experimental Investigation into Modulated Aeroacoustic Cabin Noise arising from Unsteady Flow Conditions

2025-01-0029To be published on 05/05/2025

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 an experimental approach using a large SUV-shaped vehicle to assess the effect of unsteady wind on the modulated noise performance, commonly used to evaluate unsteady wind noise characteristics. The contribution from different geometric modifications were also assessed. 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 in straight and yawed positions, to provide insight into the noise generation mechanisms and differences in behaviour between the two environments. The vehicle response to unsteady wind

Jamaluddin, Nur Syafiqah, Oettle, Nicholas, Staron, Domenic

Multi-Method Approach for car tailgate electric telescopic rod Noise: Detection, Characterization, and Prediction

2025-01-0038To be published on 05/05/2025

As the automotive industry moves towards greater intelligence, electric tailgate systems have seen widespread adoption, featuring remote control, obstacle detection, and intelligent opening functions that significantly enhance the user experience. The electric telescopic rod, as a key actuator, has drawn attention for its structural and transmission design. However, studies have shown that during actual operation, various noise issues arise with electric telescopic rods, affecting the sound quality and smoothness of the tailgate's opening and closing. This paper presents a noise detection and analysis study based on a bench test platform for a specific model of electric telescopic rod. Using a microphone to capture noise signals, three main types of noise were identified: high-frequency electromagnetic noise, low-frequency impact noise, and periodic structural noise. The study accurately detects high-frequency electromagnetic noise using wavelet packet energy feature extraction

Fan, Sibei, Wang, Siling, Zhu, Zhehui, Li, Lei, Qin, Jiade, Meng, Dejian, Pei, Kaikun

Tonal noise investigation of automotive HVAC systems : a hybrid method

2025-01-0027To be published on 05/05/2025

There is no need to recall how the electrification trend of transport facilities has tightened the requirements around acoustic comfort. Within the automotive industry, these targets are more challenging for Heating, Ventilation and Air Conditioning systems for which passengers are in the foreground of noise emissions. The complexity of the requirements and specifications set by car manufacturers and suppliers stems from a dual aspect. First is quantitative based on the sound pressure level, whether it's the overall level or 1/3 octave band spectra. The second is purely subjective based on the perceived noise quality by stakeholders and final customers worldwide. During development phases, low frequency tone noises are frequently encountered on these systems which might induce discomfort to the passengers. The experimental investigations usually point to an aerodynamic origin, which prompted this research activity. The purpose of this work is to analyze and understand the mechanism of

Bennouna, Saad, Alaoui, Mohamed, Henner, Manuel

Pass-by noise comparison of two test facilities with vehicles operating in electric mode

2025-01-0005To be published on 05/05/2025

Outdoor test facilities for light vehicle exterior noise regulatory measurement need to have surfaces certified to meet ISO 10844. A recent study considered plug-in-hybrid vehicles operating purely in electric mode to compare results at two facilities, one in Japan and in the U.S. This emphasizes the pavement contribution. Overall results are generally similar, with a few differences which are discussed.

Sorenson, Steve, Shao, Guangxin

A computational process to predict and mitigate liftgate gap noise

2025-01-0028To be published on 05/05/2025

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

Sonic Boom propagation using high and low-fidelity methods

2025-01-0034To be published on 05/05/2025

A bottle neck to the introduction of civil supersonic aircraft is represented by the noise produced by shock waves during the cruise flight, the so-called "sonic boom". Authorities prohibit supersonic flight over land due to the exceeding noise levels produced by sonic boom. This work deals with a comprehensive methodology for assessing the aircraft sonic-boom signature at ground level starting from an accurate estimation of the near-field pressure signature caused by shock-wave pressure. High fidelity computational fluid dynamics (CFD) is typically used to calculate near-field sonic booms, whereas proper models are used for propagating at long distances, since CFD becomes computationally demanding as propagation distances exceed 10 km. The present study focuses on assessing a low-fidelity technique (e.g. Whitam's equation) against the direct application of a high-fidelity CFD method for sonic boom propagation at a medium distance. The former propagates the pressure signature through

Glorioso, Antimo, Fasulo, Giovanni, Petrosino, Francesco, Barbarino, Mattia

A Comprehensive Evaluation of PU Foam for EV NVH Performance

2025-01-0120To be published on 05/05/2025

Low density polyurethane foam was first proposed as an alternative to expandable baffles and tapes for sealing vehicle body cavities towards the end of the last century. In spite of several inherent advantages for cavity sealing, the high equipment cost of dispensing amongst other reasons, this technology has not spread as widely as expected. With the advent of electric vehicles, there is an increased emphasis on controlling higher frequencies from motors, inverters and other components, and polyurethane foam can be a viable solution by providing more robust sealing. Polyurethane foam sealing is already being employed in the new breed of electric vehicles but its NVH advantages have not been fully studied or published in literature. Using an existing electric vehicle with conventional expandable baffles & tape sealing measures, a comprehensive evaluation of NVH performance using the closed-cell polyurethane foam solution was carried out. Testing included component level bench test on

Kavarana, Farokh, Guertin, Bill

Reducing LiDAR Cabin Noise with Damped Elastomers: a Novel Method for Predicting Performance and Durability

2025-01-0114To be published on 05/05/2025

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

A Study on Reduction of Gear Rattle Noise through Clutch Hysteresis Stabilization

2025-01-0100To be published on 05/05/2025

Reducing gear rattle noise within the passenger cabin is a crucial objective in vehicle development due to its direct impact on customer comfort and driving experience. Gear rattle occurs when free gears collide during meshing, primarily driven by high torsional vibrations generated by engine fluctuations. These vibrations are transmitted through the clutch system to the transmission, amplifying noise inside the cabin. To address this issue, this study focuses on optimizing the clutch by stabilizing its hysteresis, which helps in minimizing the torsional vibrations transferred to the transmission input shaft, thereby reducing gear rattle. The investigation centers on a case where significant gear rattle was observed at high vehicle speeds, particularly under high engine torque conditions. A thorough root cause analysis identified that the primary contributor to the noise was a drop in the clutch hysteresis value at elevated engine torques. This drop increased torsional vibrations in

Awasthi, Mradul, Dhankhar, Dinesh Singh, Khare, Devendra Kumar, Rana, Deepak, Pandey, Anant

Methodology for Radiated Noise Refinement of Electrified Drivetrain Systems

2025-01-0098To be published on 05/05/2025

Electric drive units (EDU) of battery electric vehicles and electric drivetrain components of hybrid vehicles require significant development effort and planning to ensure that a refined NVH sound quality is achieved. New tools and methods are required to understand the NVH performance throughout the development process and to ensure that NVH risks can be quickly identified and mitigated within the correct EDU subsystems. This paper discusses the development of a methodology (EDSL – Electric Drive Sound Level) aimed at addressing this need. It also outlines how the EDSL tool can be used to address radiated noise issues and understand the NVH performance of the various subsystems within an electrified drivetrain component. The first use of the EDSL methodology is to characterize component-level radiated noise test results and compare the different mechanical and electrical noise sources to targets. The results from this are used to guide EDU development in the appropriate areas

Pruetz, Jeffrey E., Steffens, Christoph, Fu, Tongfang, Ford, Alex

Impact of tripod joint pressing load variation on drive shaft rattling in passenger car

2025-01-0097To be published on 05/05/2025

In today’s fast changing and competitive automotive world, vehicle NVH plays an important role in customer’s perception of the brand. A silent cabin with lower noise levels is a desired attribute in a modern car. In such a scenario, abnormal noises arising because of manufacturing variations and tolerances of components can impact the brand image of any automotive company negatively. This paper presents an investigation into a noise issue arising from the right-hand (RH) drive shaft of an automotive vehicle while driving on rough roads at approximately 30 km/h. Various technical measurements, including rotational backlash and dimensional assessments, were conducted, all of which were found within specification. However, axial play between the tripod spline and the mid-shaft spline was identified during disassembly. Further analysis revealed that material localization was the only change point in the RH drive shaft manufacturing process. The fit interference between the tripod spline

Dhankhar, Dinesh Singh, Mishra, Ashish, Kirti, Viplav, Rana, Deepak, Bhardwaj, Ashish, Singh, Karanveer

Leveraging Vision Language Models and Prompt Engineering for Bearing Defect Classification from Vibration Signals

2025-01-0127To be published on 05/05/2025

Bearings are fundamental components in automotive systems, ensuring smooth operation, efficiency, and longevity. They are widely used in various automotive systems such as wheel hubs, transmissions, engines, steering systems etc. Early detection of bearing defects during End-of-Line (EOL) testing and operational phases is crucial for preventive maintenance, thereby preventing system malfunctions. In the era of Industry 4.0, vibrational, accelerometer, and other IoT sensors are actively engaged in capturing performance data and identifying defects. These sensors generate vast amounts of data, enabling the development of advanced data-driven applications and leveraging deep learning models. While deep learning approaches have shown promising results in bearing fault diagnosis, they often require extensive data, complex model architectures, and specialized hardware. This study proposes a novel method leveraging the capabilities of Vision Language Models (VLMs) and Large Language Models

Chandrasekaran, Balaji, Cury, Rudoniel

Cabin noise modeling for seat location variation using AI and Machine Learning

2025-01-0129To be published on 05/05/2025

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, He, Junyan, Banerjee, Bhaskar

Pass-by Noise Contribution Analysis of an Agricultural Tractor

2025-01-0134To be published on 05/05/2025

There is an increasing effort to reduce noise pollution across different industries worldwide. From a transportation standpoint, pass-by regulations aim to achieve this and have been implementing increasingly stricter emissions limits. Testing according to these standards is a requirement for homologation but does little to help manufacturers understand why their vehicles may be failing to meet limits. Using a developed methodology such as Pass-by Source Path Contribution (SPC, also known as TPA) allows for identification of dominant contributors to the pass-by receivers along with corresponding acoustic source strengths. This approach is commonly used for passenger vehicles, but impractical for off-highway applications, where vehicles are often too large for most pass-by-suitable chassis dynamometers. A hybrid approach is thereby needed, where the same techniques and instrumentation used in the indoor test are applied to scenarios in an outdoor environment. This allows for

Freeman, Todd, Engels, Bret, Thuesen, Ben

100+ Years of Noise and Vibration in the Auto Industry

2025-01-0071To be published on 05/05/2025

There have been advances in the area of noise and vibration for over 100 years in the auto industry. This presentation will highlight some of the driving forces and advances over that period.

Kach, Raymond, Thompson, James

High-resolution option for the Sottek Hearing Model Tonality enables accurate order analysis

2025-01-0093To be published on 05/05/2025

The Sottek Hearing Model provides a comprehensive framework for understanding the nuances of sound perception, including such aspects as loudness, tonality, roughness, fluctuation strength, sharpness, and impulsiveness. The principal model was first published more than three decades ago as part of a doctoral thesis. Over the past few decades, the model has been refined and recently standardized in the international standard ECMA 418-2. This standard addresses several psychoacoustic parameters, including a new approach to time-varying loudness based on a nonlinear combination of partial tonal and noise loudness. This is the preferable approach because the loudness of tonal components (i.e., tonal loudness) may have a more pronounced impact on loudness perception than the loudness caused by other components (i.e., noise loudness). Other standardized parameters include tonality and psychoacoustic modulation analyses. These comprise roughness, which is employed to evaluate rapidly

Sottek, Roland, Bray, Wade

Electric Bus NVH Challenges and Refinement Using Innovative Approach

2025-01-0080To be published on 05/05/2025

The trend towards electrification propulsion in the automotive industry is highly in demand due to zero-emission and becoming more significant across the world. Battery electric vehicles have lower overall noise as compared to conventional I.C Engine counterparts due to the absence of combustion engine noise. However, other narrowband and tonal noises are becoming dominant and are strongly perceived inside the cabin. With the ongoing push towards electrification, there is likely to be increased focus on the noise impact of gearing required for the transmission of power from the electric motor to the road. Direct coupling of E-motors with Axle has resulted in severe tonal noises from the driveline due to instant e-motor torque ramp up from 0 rpm and reverse torque on driving axle during regenerative braking. The tonal noises from the rear axle during vehicle running become very critical for customer perception. For automotive NVH engineers, it has become a challenge to balance expected

Doshi, Sohin, Kalsule, Dhanaji, Sawangikar, Pradeep, Suresh, Vineeth, Sharma, Manish

The quality of vehicle horn sounds research and control

2025-01-0088To be published on 05/05/2025

Chinese consumers are very concerned about the quality of vehicle horn sounds, and the quality of vehicle horn sounds is very important in the overall NVH development process. This paper studies the sound quality of vehicle horns based on their working principles and characteristics, combined with the principles of vehicle vibration and noise control. It conducts research on the sound quality of vehicle horns from multiple dimensions, including vibration and noise excitation sources, transmission paths, and evaluation conditions. By analyzing the horn sound quality problems encountered in the development process of a certain domestic new energy vehicle, it proposes corresponding solutions. The results show that in addition to the common NVH phenomena of vehicle horns, the vibration and noise of vehicle horns can cause nonlinear phenomena in adjacent components, thereby producing abnormal noise. This study provides technical reference for nonlinear research and control of vehicle horn

Li, Zhigi, Zhou, Changshui, Xie, Kai, Wangqiyuan, 琦渊, Mao, Quangjun

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