Browse Topic: Interior noise

Items (453)

Electric vehicle road noise analysis through systematic virtual prototyping

2024-26-022401/16/2024

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

Countermeasures for Low Frequency Boom noise Reduction in Electric Vehicle

2024-26-021401/16/2024

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

Investigating The Factors Affecting Cabin Comfort for Agricultural Machinery

2024-26-006701/16/2024

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

Correlated beamforming based on deconvolution methods for identified vehicle exterior wind noise sources and interior noise

2025-01-002505/05/2023

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

Leveraging user feedback to optimize the tuning of EVSE models

2025-01-002005/05/2023

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

HV-BATTERY IMPACT ON CAR BODY ACOUSTICS AND DAMPING PACKAGE OPTIMIZATION OF THE ELECTRIC VEHICLE

2025-01-004105/05/2023

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

Underbody contribution simulation for vehicle wind-noise.

2025-01-002605/05/2023

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

Characterization and Prediction of Interior Noise Quality in Electric Vehicles through Drive Unit End-of-Line Testing (EOLT)

2025-01-003905/05/2023

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

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

2025-01-002905/05/2023

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

A computational process to predict and mitigate liftgate gap noise

2025-01-002805/05/2023

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 Strategy

2025-01-006305/05/2023

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

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

2025-01-012905/05/2023

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

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

2025-01-011405/05/2023

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 Cruise

2022-01-078203/29/2022

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 Modelling

2022-01-036103/29/2022

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 Future

2021-26-027209/22/2021

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 Vehicles

2021-26-028309/22/2021

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

Subjective and Objective Seat Feature Acoustic and Vibration Response

2021-01-107508/31/2021

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

The Noise and Vibration Response of Eight Light Vehicles on Sinusoidal and Conventional Rumble Strips

2021-01-110608/31/2021

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 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 ear location and five around where a front seat passenger would be located for three 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

Donavan, Paul R., Janello, Carrie

Experiencing the Benefit of Optimized Laminated Glass Interlayer Material Using a Driving Simulator for NVH

2021-01-106608/31/2021

In this paper, we present the process we propose to evaluate the effect of the laminated glass interlayer material on the Noise, Vibration and Harshness (NVH) performance of vehicles. The process starts from lab measurements to evaluate the glass damping and sound transmission loss and demonstrate the benefit of using optimized interlayer material. The results are then used to develop filters to adapt a vehicle model created in a driving simulator for NVH. With this process, it is not necessary to physically install the windshield in the vehicle to be able to listen and experience the benefits of switching to an optimized interlayer material. We use results from a real application case to verify the validity of the process and we share in our conclusions the future direction for this work to make the process completely virtual by using CAE simulation data.

Takeda, Yuma, Sakamoto, Yumiko, Yoshida, Shogo, Hadjit, Rabah, Iwamoto, Tatsuya

Numerical Investigation of Tonal Noise at Automotive Side Mirrors Due to Aeroacoustic Feedback

2020-01-151406/03/2020

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 Module

2020-01-127504/14/2020

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

Vibrational Analysis Method on High-frequency Electric-drive Motor Noise

2020-01-046304/14/2020

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

Acoustic performance analysis of automotive HVAC duct designs using a Lattice-Boltzmann based method and correlation with Semi-anechoic chamber.

2020-01-126304/14/2020

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

The Resolution of 8th Order Whining Noise for a Battery Electric Vehicle

2020-01-126904/14/2020

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

A Case Study on Reducing the Fuel Pulse Noise from Gasoline Engine Injectors

2020-01-127604/14/2020

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

Applications of Strain Measurements to Improve Results on Transfer Path Analysis

2019-36-032301/13/2020

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 Engine

2019-01-230412/19/2019

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 cabins

19AUTP10_1110/01/2019

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 Evaluation

02-12-03-001407/03/2019

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

A Comparison of Two Source Characterisation Techniques Proposed for Standardisation

2019-01-154006/05/2019

Automotive industry shows an increased tendency towards characterisation of vibration sources by independent quantities such as blocked forces and free velocities. Currently two independent ISO working groups propose standards for this source characterisation process. Both standards are still under development. In this paper it is shown how the different approaches can be derived and compared using the general framework for Transfer Path Analysis (TPA). It is shown how one standard clearly relates to classical TPA methods (using interface forces), while the other standard adheres the component-based TPA principles (using blocked forces). Practical guidelines found in the standard proposals are reviewed, allowing for a qualitative comparison of the proposed procedures. To address typical problems regarding completeness of the interface, an addition is proposed that incorporates the use of 6-DoF Virtual Point forces and moments. It is shown how this approach can be applied to any force

van den Bosch, Daniël, van der Seijs, Maarten, de Klerk, Dennis

Assessment of Automotive Environmental Noise on Mobile Phone Hands-Free Call Quality

2019-01-159706/05/2019

Environmental noises such as wind, road, powertrain, and HVAC noise are important aspects to consider when implementing a hands-free terminal for mobile phone calling from within a car. Traditionally, these environmental noises have been exclusively considered for driver comfort; however, with the introduction of the hands-free terminals (HFT) and increasing consumer demand relative to mobile phone call quality, a broader implication of high background noise levels should be considered. HFT algorithm development and implementation can and does provide a high level of background noise suppression to mitigate these concerns, but this is often done at the expense of computational power and cumulative delay during a phone call. The more advantageous solution would be to address the problem from a source and path perspective with emphasis on reduction of noise in the frequency bands which most influence call quality performance. The assessments shown throughout this paper establish a

Pruetz, Jeffrey, Watson, Channing, Tousignant, Todd, Govindswamy, Kiran

New Psychoacoustic Criteria for Turbocharger Aero Noise

2019-01-148906/05/2019

With ever more stringent regulations related to air pollution and CO2 emissions, there is a growing trend to address this through the downsizing of automotive engines. Turbochargers are used to improve engine power by using exhaust gas energy to provide boosted air pressure for better efficiency. They are a key element in powertrains of today and in the future. During real operating conditions, the rotational speed of a turbo varies greatly making this rotating machinery run in “continuous transient” phases and produces unwanted noises as a result. Recently, we identified a new source of aero noise while developing a new type of turbocharger. Our typical in-house procedure for characterizing usual aero broad band noise source was to use the 3-microphone methodology for measuring the acoustic intensity. However, this methodology is not well adapted if the noise source is tonal, not constant over time and includes high frequency content, which is the case with the new type of

Rigault, Alexandre, Kihm, Fred, Baron, Nicolas

Subband Adaptive Filtering Algorithms for Active Broadband Noise Control in Impulsive Vehicle Noise Environment

2019-01-152806/05/2019

Subband adaptive filtering (SAF) techniques have been increasingly used in active noise control (ANC), especially for acoustic broadband noise signal and system models with long impulse responses. In ANC, the closed-loop delayless SAF schemes improve the convergence rate of the widely adopted conventional filtered-x LMS (FxLMS) algorithm in a more computationally efficient manner under wideband noises like colored signals or even nonstationary signals. In most real-world environment like vehicle interior cabin, however, the performance of ANC can be degraded by various outliers, including non-Gaussian impulsive signal such as transient impact acoustic response for road noise. Although several robust objective error criteria as well as threshold based LMS-type adaptive filtering algorithms have been investigated for active impulsive noise control, the computational burden would be challenging for implementation and the requirement of a priori knowledge of noises cannot be fulfilled in

Long, Guo, Wang, Kan, Lim, Teik

Driveline NVH Integration of An NA Truck Program

2019-01-155906/05/2019

In the current automotive industry, it is common that the driveline subsystem and components are normally from different automotive suppliers for OEMs. In order to ensure proper system integration and successful development of driveline system NVH performances, collaboration efforts between OEMs and suppliers are very demanding and important. In this paper, a process is presented to achieve successfulness in developing and optimizing vehicle integration through effective teamwork between a driveline supplier and a major OEM. The development process includes multiple critical steps. They include target development and roll down, targets being specific and measurable, comprehension of interactions of driveline and vehicle dynamics, accurate definition of sensitivity, proper deployment of modal mapping strategy, which requires open data sharing; and system dynamics and optimization. More specially, the supplier can work with OEM to seek the most cost-effective solutions, through tuning

Peng, Ying, Shi, Zhenghong, Folts, Christopher, Kopp, Gregory, Sun, Zhaohui, Sandstrom, Alexander

Performance Testing and Analysis of Multi-Channel Active Control System for Vehicle Interior Noise Using Adaptive Notch Filter

2019-01-156706/05/2019

It is considered that slow convergence speed and large calculation amount of commonly used adaptive algorithm in the active control system for vehicle interior noise yield noise reduction performance and hardware requirements problems. In this paper, a 4-channel active control of vehicle interior noise based on adaptive notch filter is established, and road test is carried out to test and analyze the performance of the control system. Firstly, the general mathematic model of the multi-channel active control system based on adaptive notch filter is established. The computational complexity of the algorithm is analyzed and compared with that of the FXLMS algorithm. Secondly, a hardware-in-the-loop test bench based on multi-channel adaptive notch filter is set up, to measure the noise reduction performance of ANC system under various working conditions. Finally, the typical test conditions are designed to test the system noise reduction performance, and the road test is carried out and

Zhang, Lijun, Zhang, Xiyu, Meng, Dejian

A Research on Vehicle Gearbox Whine Based on Multi-Physics Coupling Simulation and Psychoacoustics

2019-01-077904/02/2019

Vehicle gearbox whine is a common NVH problem which may directly cause complains from passengers on the quality and performance of vehicle. In order to efficiently and fundamentally control the whine phenomenon, this work first studied the characteristics and mechanisms of the gearbox vibration and noise. The study results revealed that the transmission error of gear was the excitation source of gearbox vibration, and the ambient air was the main transfer path of radiation noise. Then a multi-physics coupling simulation model was built to reveal the interactions among gear, housing and ambient air. This model could also predict the characteristics of the sound field near the passenger’s ear. To take account the psychoacoustic property of human auditory system, this work applied a quality index called tonality to evaluate the severity of gearbox whine. This paper also describes a case study to verify the accuracy and availability of the simulation model. In this case, the whine

Tang, Sicheng, Xu, Yong

Streamlined HMIs do more with less

19TOFHP04_0804/01/2019

The phrase “less is more” has been a major part of human-machine interface (HMI) designs for several years as developers traded multiple knobs and buttons for cleaner input techniques. However, the push to simplify the control's look and feel is offset by the need to let drivers and operators manage more things, often with redundant input techniques. The growing number of electronic features and functions comes as vehicle buyers demand controls that can be learned quickly. This need to manage more complex tasks without much training marks a major change from the era when operators slowly learned how to maneuver mechanical controls. New designs will need to further simplify the vehicle environments designed to provide more digital functionality.

Costlow, Terry

Design, Simulation & Optimization of an Air Intake System to Reduce Induction Noise

2019-26-019101/09/2019

Air intake system (AIS) plays a major role in reducing the noise level in passenger car compartment, which has become an important requirement due to increasing customer expectation for better in cab noise. The ideal air intake system design should have minimum possible noise at snorkel entry point which ultimately contributes in cabin noise. There are different techniques that are implemented for an air intake system noise reduction e.g. choosing proper location of air entry suction point in engine bay compartment, suitable design for air filter box (volume), duct designs etc. Further design improvement are possible with an addition of tuned resonators in the system. An addition of resonator have major effect seen in reducing air induction noise and to meet target Sound Pressure Levels (SPL). But at the same time, selecting the correct type of resonator, its position & volume, frequency/s band at which resonator is tuned are important parameters. The work presented here describes and

Patil, Ujwal, Rahane, Dnyanesh

Design Optimization of Engine Mount De-Coupler for Cabin Noise Refinement in Passenger Vehicle

2019-26-019901/09/2019

Quieter cabins are indispensable in today’s evolving automobile industry. The effective isolation of vehicle noise and vibrations are essential to achieve the above. Since, low frequency powertrain induced NVH has been one of the major contributors affecting noise and vibration levels inside the passenger cabin. Thus, use of hydraulic mounts is a natural choice for all major OEMs. The objective of this study is to optimize the design of the hydraulic mount de-coupler unit, to reduce the abnormal noise felt inside the cabin. This condition was observed when the vehicle was driven at 20~30 km/h over undulated road surface, found very often in Indian drive conditions. Due to lack of accuracy and repeatability errors during NVH data acquisition in actual driving condition, the above road profile was captured and subsequently simulated in an acoustically treated BSR (Buzz, Squeak and Rattle) four poster simulator. Problem investigation and countermeasure validation were also performed in

Verma, Pallavi, Chatterjee, Joydeep, Bhadani, Priyesh, Ghosh, Chiranjit

Investigation of Cabin Noise while Accelerating on Low Mu Track through Simulation Approach Using Full Vehicle ADAMS/Car Model

2019-26-017901/09/2019

Cabin noise is a significant product quality criteria which enables the customers for product differentiation. There are various sources of cabin noise such as wind, structures(panels), engine, suspension, tire and roads. During product development phase, extensive tests has been conducted to improve vehicle dynamics behavior on various climatic conditions. One such test is accelerating vehicle on low mu or icy surface. While performing acceleration manoeuvre (tractions) on a low mu tracks, Cabin noise with source identified from front underbody & low tractive torque build up is reported. This undesirable behavior may occur due to following reason (1) Excitation of coupled modes between suspension and powertrain which induces torque fluctuation. (2) Transmissibility of various subsystem can be the reason for above problem statement. (3) Poorly chosen tire compounds and design leads to fluctuation in torque. A detailed simulation based study using ADAMS/CAR has been performed to assess

Singh, Vivek, Prasad, Tej, Srivastava, Harshit

Low Frequency In-Cab Booming Noise Reduction in the Passenger Car

2019-26-017101/09/2019

In-cab booming noise is low frequency (20 Hz∼300 Hz) phenomenon excites the cabin structure, which occurs mainly due to excitations from the powertrain, exhaust system, road input, etc. Annoyance due to booming noise affects the In-cab sound quality, which results in passenger discomfort. A diesel passenger car observed booming noise issue when operated at stationary as well as dynamic run-up conditions. In order to increase passenger comfort, experimental root cause analysis conducted on the vehicle to investigate the dominant sources for the cavity boom. Exhaust hanger and one of the engine mount identified as major reason for the booming noise in the cabin. A detailed study was carried out on dynamic property optimization of rubber hanger and possibility to relocate the hanger to improve the vibration transmissibility. Operational measurements conducted on vehicle by attaching finalized exhaust mount to confirm the significant booming noise reduction in the cabin.

Jawale, Pradeep, Karanth, Nagesh Voderahobli, Gaikwad, Atul Annasaheb, Mutalik, Keshav

Force Transmission Characteristics for a Loaded Structural-Acoustic Tire Model

06-11-04-002510/23/2018

Concerns about tire noise radiation arise partly from city traffic planning, environmental protection, and pedestrian safety standpoints, while from the vehicle passengers’ perspective, noise transmitted to the vehicle interior is more important. It is the latter concern that is addressed in this article. Sound-absorbing materials generally offer good absorption at higher frequencies, but the reduction of relatively low frequency, structure-borne tire noise is a continuing focus of many auto manufacturers. A tire’s internal, acoustic cavity resonance is a very strong contributing factor to tire-related structure-borne noise, and it can easily be perceived by passengers. Some reduction of vehicle cabin noise can be achieved through the insertion of sound-absorbing material in the tires. However, apart from the additional cost for such tires, there is also an increased complexity when repairing them because of the need to avoid damaging the sound-absorptive lining. In that light

Cao, Rui, Bolton, J. Stuart

The Effects of Suspension Component Stiffness on the Road Noise: A Sensitivity Study and Optimization

2018-01-151006/13/2018

This paper investigates the sensitivity of stiffness of front and rear suspension systems on the structure-borne road noise inside a vehicle cabin. A flexible multi-body dynamics based approach is used to simulate the structural dynamics of suspension systems including rubber bushings, suspension arms, a subframe and a twist beam. This approach can accurately predict the force transfer to the trimmed body at each suspension mounting point up to a frequency range of 0 to 300 Hz, which is validated against a force measurement test using a suspension test rig. Predicted forces at each mounting point are converted to road noise inside the cabin by multiplying it with experimentally obtained noise transfer functions. All of the suspension components are modeled as flexible bodies using Craig-Bampton component mode synthesis method. To conduct a sensitivity analysis of the rubber bushings’ stiffness, an accurate nonlinear dynamic model of rubber bushings is constructed and validated against

Kim, Joong-Kwan, Lee, Jinmo, Kim, Hyoung-Gun, Cho, Munhwan, Ih, Kang-Duck, Ko, Han-Young, Shim, Jeong-Soo

Optimizing Vehicle NVH Using Multi-Dimensional Source Path Contributor Paradigm.

2018-01-154206/13/2018

Automotive Industry is moving towards lightweight vehicle design with more powerful engines. This is increasing a demand for more optimized NVH design. Source-Path-Contributor (SPC) analysis is one of the ways to draw a holistic picture of any NVH problem. In this paper, an NVH problem of low frequency booming noise and steering vibration has been studied in a development vehicle. All three dimensions of SPC paradigm were looked at to propose a feasible and optimized solution at each level of Source, Path and Contributor model. A classical transfer path analysis (TPA) has been done to identify the highest contributing path: transmission mount and suspension arm. Optimization of suspension bush parameter has been carried out using dynamic elastomer testing facility for an improved NVH performance. After identifying source as engine a study of torsional fluctuations due to gas pressure and torsional resonances has been carried out in order to achieve a feasible solution at source

Gupta, Gaurav, Singh, Vivek

Interior Noise Refinement in an ICV Bus through Driveline Torsional Vibration Analysis

2018-01-147206/13/2018

With a push for urbanization across cities, there is an increased demand for mobility in public transportation especially buses which are provided through state transport undertakings. Hence, the expectations of this class of vehicles will be high in terms of quality and comfort to the passengers. The noise inside the passenger area of the bus becomes an important parameter, which sets apart a bus manufacturer from its competitors. The driveline of the bus is the system responsible for the transfer of power from engine to the wheels. The noise and vibration problems associated with it are detected only in the late stages of the design chain, when all its elements are tested together over a wide range of conditions. Since, calibration of engine and the selection of transmission is freezed in early stages, satisfying power and torque requirements, the only viable option left to address the problem is by optimizing the clutch parameters. Combustion in multi-cylinder four stroke diesel

Kamani, Keval, Kannan, P, P, Sivaraman

Squeak Noise Prediction for Systems with Dry Friction Damping

2018-01-148306/13/2018

Squeak noise is a phenomenon which is often categorized as BSR, i.e. buzz, squeak and rattle. It arises from stick-slip movement between parts in contact. In a vehicle cabin, this noise is undesirable and has to be prevented. Simulation methods are used to find critical contact conditions in the construction at an early stage of development. For accurate predictions, these methods have to take nonlinear behavior into account. In this paper, the Harmonic Balance Method is applied to a three-dimensional finite element model in order to calculate vibrations of systems with dry friction contacts. The system’s sensitivity to different contact formulations is investigated. For a reference, a test rig has been built. It consists of a beam with harmonic excitation. The beam is clamped at one end. At the other end it is in dry friction contact with a plate. Different excitation levels, frequencies, normal contact forces and material pairs are evaluated. The system’s response in time and

Weisheit, Konrad, Marburg, Steffen

Challenges of Hydraulic Engine Mount Development for NVH Refinement

2018-01-068104/03/2018

NVH refinement of passenger vehicle is essential to customer acceptance for premium or even mid-size segment passenger cars. Hydraulic engine mount is becoming common for these segments to reduce engine bounce, idle shake and noise transfer to passenger cabin. Modern layout of hydraulic mount with integrated engine-bracket and smaller size insulator has made it cost-effective to use due to reduction of cost gap from conventional elastomeric mounts. However the downsizing and complex internal structure may create some new types of noises in passenger cabin which are very difficult to identify in initial development stage. Main purpose of hydraulic mount is to provide high damping at low-frequency range (6~15 Hz) and to isolate noise transfer from combustion engine to passenger cabin within wide frequency range (15~600 Hz).This paper emphasizes on challenges and problems related to hydraulic mount development. Tuning of Hydraulic mount is required to avoid cavitation noise at low

Ghosh, Chiranjit, Parmar, Aashish, Chatterjee, Joydeep

An Objective Assessment Method of Combustion Noise Characteristics in Vehicle Interiors

2018-01-128304/03/2018

To increase the efficiency of measures targeting combustion noise in complete vehicle development, the authors developed a new sound quality evaluation method by combining two known methods: the time domain combustion noise separation method (T-CNSM) and a psychoacoustic metric, fluctuation intensity. The T-CNSM was applied to the vehicle interior noise, allowing for precise extraction of the combustion contribution in the time domain. Furthermore, the T-CNSM has enabled a sound quality check of combustion noise using a headphone-playback system. The procedure of this method is as follows. Firstly, simultaneous measurement of vehicle interior noise and in-cylinder pressure of each cylinder is carried out under acceleration. Afterward, the application of digital signal processing using Fourier transform and multiple regression analysis to the measured data extracts the contribution of combustion noise from the vehicle interior noise in the time domain. Subjective evaluation tests using

Torii, Kenji, Noumura, Kousuke

Research of Effect of Electric Powertrain on Vehicle Noise

2018-01-128204/03/2018

A low-speed and heavy-duty electric powertrain was selected as the research object, the influence of electric powertrain characteristics on whole vehicle noise under accelerating condition (Speed range 800 r∙min−1~2200 r∙min−1; Torque range 500 N∙m~960 N∙m) was studied. Considering the traveling characteristics around the city, the interior and powertrain noise were recorded as the accelerating working range (10 km/h~50 km/h). Based on recording data, combining the noise generation mechanism of the motor and transmission, the components of the interior noise and motor/transmission noise were analyzed qualitatively using the order spectrum analysis; the contribution of the electric powertrain noise components to the interior were calculated quantitatively using the partial coherence analysis method; finally the measuring and analyzing methods of effect of electric powertrain on interior were built, which provided certain theoretical support for further improving the noise of electric

Liu, Hai, Ma, Kunqi, Yu, Hanzhengnan

Items per page:

1 – 50 of 453