Browse Topic: Noise

Items (6,021)
The operator station or “cab” in off Highway equipment plays a critical role to provide a comfortable workspace for the operator. The cab interfaces with several elements of the off-highway equipment which can create gaps and openings. These openings have the potential for acoustic energy leakage, ultimately increasing sound within the cab. During machine operation, noise generated around the cab conducts inside through these leakages resulting in increased sound levels. Acoustic leakages are among the key noise transfer paths responsible for noise inside the cab. Therefore, before considering noise control treatments it is best to first identify and minimize any leakages from joints, corners, and pass-throughs to achieve the required cab noise reduction. In this effort the sound intensity technique is used to detect the acoustic leakages in cab. The commercial test system is used for measuring the sound intensity field over objects. For the cab, an acoustic source is used inside the
Pawar, Sachin M.Mandke, DevendraFapal, AnandCone, Kerry
The new Stage 5 emission regulation requires several changes on engines as well as design and development of new auxiliary systems. These changes affected the engine dynamics and NVH characteristics. These changes are validated for various operating conditions on engine test cell in a controlled environment where engine is mounted on test cell with dyno. Further, this engine will be used by other machine forms, hence NVH performance needs to be evaluated for all the applications. Isolation of three-cylinder engines is challenging since it has to deal with inherent imbalance forces while providing the isolation to meet the durability requirements of heavy applications from off highway machines. This paper covers the methods used for verification of engine isolation performance. NVH tests are conducted for integration of three-cylinder engine with roadbuilding machine. An analytical model is developed to identify rigid body modes and mount transmissibility. Results from this analytical
Pawar, Sachin M.Mandke, Devendra LaxmikantKASABE, SANDEEPJadhav, Vijay
Traditionally, off-highway vehicles like tractors and construction machinery have relied on hydraulic, viscous, or fixed fans to meet the cooling demands of diesel engines. These fans draw power from the engine, impacting fuel consumption and contributing to noise levels that affect operator comfort. Recently, the adoption of electric fans in off-highway applications has increased due to their energy efficiency, lower noise, and flexible design. Electric fans can cool various components, such as radiators and condensers, and can be positioned for optimal performance. They are easily selected from established supplier catalogs based on application requirements like machine voltage, fan size, and type. This study explores various fan arrangements, including pusher and puller types, and multiple electrical fan banking based on cooler zones to improve cooling system performance without changing cooler size or specifications. A mathematical flow model was developed for both setups: the
Durairaj, RenganathanDewangan, NitinAnand, KetanBhujbale, Sagar
Noise pollution from automotive vehicles is a significant concern in urban areas, emphasizing the need for improved vehicle engineering of automotive vehicles to reduce noise levels. The necessity for automotive vehicles to have a low acoustic signature may further be emphasized by local regulatory requirements, such as the EU's regulation 540/2014, which sets sound level limits for commercial vehicles at 82 dB(A). In addition to this the external noise may propagate inside the cabin affecting the overall wellbeing of the driver. To address the issue vehicles are observed to measure noise levels at various locations, including inside and outside the cabin. These testing facilitate noise source identification and categorization of noise into structure-borne noise and air-borne noise. The air-borne noise, which can be either broadband or tonal in nature, is particularly discomforting and may require mitigation. To analyse these complex aero-acoustic behaviour of the vehicle, CFD can be
Sharma, ShantanuPawar, Sourabhsingh, RamanandKalamdani, Sreenath
Noise generated by a vehicle’s HVAC (Heating, Ventilation, and Air Conditioning) system can significantly affect passenger comfort and the overall driving experience. One of the main causes of this noise is resonance, which happens when the operating speed of rotating parts, such as fans or compressors, matches the natural frequency of the ducts or housing. This leads to unwanted noise inside the cabin. A Campbell diagram provides a systematic approach to identifying and analyzing resonance issues. By plotting natural frequencies of system components against their operating speeds, Test engineers can determine the specific points where resonance occurs. Once these points are known, design changes can be made to avoid them—for example, adjusting the blower speed, modifying duct stiffness, or adding damping materials such as foam. In our study, resonance was observed in the HVAC duct at a specific blower speed on the Campbell diagram. To address this, we opted to optimize the duct design
Trivedi, ArpitaKumar, RaviMadaan, AshishShrivastava, Pawan
This study demonstrates the application of the T-Matrix, a Total Quality Management (TQM) tool to improve thermal comfort in automotive climate control systems. Focusing on the commonly reported customer issue of insufficient cabin cooling, particularly relevant in hot and congested Indian driving conditions, the research systematically investigates 36 failure modes identified across the product lifecycle, from early design through production and post-sale customer usage. Root causes are first categorized using an Ishikawa diagram and then mapped using the T-Matrix across three critical stages: problem creation, expected detection, and actual detection. This integrated approach reveals process blind spots where existing validation and inspection systems fail to catch known risks, particularly in rear-seat airflow performance and component variability from suppliers. By applying this TQM methodology, the study identifies targeted improvement actions such as improved thermal targets
Jaiswara, PrashantKulkarni, ShridharDeshmukh, GaneshNayakawadi, UttamJoshi, GauravShah, GeetJaybhay, Sambhaji
To address the growing concern of increasing noise levels in urban areas, modern automotive vehicles need improved engineering solutions. The need for automotive vehicles to have a low acoustic signature is further emphasized by local regulatory requirements, such as the EU's regulation 540/2014, which sets sound level limits for commercial vehicles at 82 dB(A). Moreover, external noise can propagate inside the cabin, reducing the overall comfort of the driver, which can have adverse impact on the driving behavior, making it imperative to mitigate the high noise levels. This study explores the phenomenon of change in acoustic behavior of external tonal noise with minor geometrical changes to the A-pillar turning vane (APTV), identified as the source for the tonal noise generation. An incompressible transient approach with one way coupled Acoustics Wave solver was evaluated, for both the baseline and variant geometries. Comparison of CFD results between baseline and variant showed
Pawar, SourabhSharma, ShantanuSingh, Ramanand
The current automotive development cycle is becoming shorter and shorter, therefore research is needed to improve the efficiency of wind noise transient calculation. This article summarizes 14 internal and external factors that affect the efficiency and accuracy of transient analysis of wind noise, and uses the ULH algorithm to design DOE for these 14 factors. A total of 200 efficiency improvement schemes are generated, and transient analysis is conducted on each of the 200 schemes. The simulation results and calculation time of wind noise inside the vehicle are statistically analyzed. And aerodynamic acoustic wind tunnel tests were conducted to verify this, with the optimization objectives of simulation values approaching 86.1 AI% (experimental values) and shortened calculation time. NSGA-II algorithm was used to optimize and obtain five sets of efficiency combination schemes that meet the requirements. Develop five appearance feature schemes for areas such as A-pillar and rearview
Li, XiangliangZhang, XiangdongLiu, XuelongWang, HaiyangHuang, Zhongyuan
In recent years, traffic issues in China have been emerging continuously, and the traffic congestion problem in Beijing is particularly prominent. We have explored the relationships between factors such as driving duration, road length, weather conditions in Beijing and traffic congestion. By using the Logistic Regression Model to analyze the relationships among driving duration, road length and traffic congestion, we found that both driving duration and road length are negatively correlated with traffic congestion. The model shows high accuracy and recall rate, demonstrating excellent performance. We also employed the Weighted Average Correlation Model to study the relationship between weather conditions and traffic congestion. The results indicate that traffic congestion is more severe in rain, snow, and foggy weather, while it is less serious in sunny and cloudy weather. Subsequently, through the noise level verification, the stability of the model was confirmed. At the same time
Feng, JiaruiHan, Xiran
With the escalating rate of urbanization in China, the urban construction sector is encountering numerous challenges, including issues such as traffic congestion and environmental pollution. To enhance traffic efficiency and offer planning guidance for urban development, this study focuses on the fully or partial opening of community entrances. VISSIM is utilized to examine the community opening and simulate the internal road network, while also employing the SPSS data analysis tool for supplementary analysis. The objective of this method is to compare and analyze the traffic conditions and environmental impact of the community before and after its opening with different automobiles. Through the establishment of a comprehensive evaluation system, the study calculates and analyzes the average vehicle speed, noise levels, energy consumption, and carbon dioxide emissions before and after the opening of the community. Finally, several recommendations are proposed to enhance community
Li, MengyuanZhuo, ChenxuXiong, SiminXu, Lihao
An important characteristic of battery electric vehicles (BEVs) is their noise signature. Besides tire and wind noise, noise from auxiliaries as pumps, the electric drive unit (EDU) is one of the major contributors. The dynamic and acoustic behavior of EDUs can be significantly affected by production tolerances. The effects that lead to these scatter bands must be understood to be able to control them better and thus guarantee a consistently high quality of the products and a silent and pleasant drive. The paper discusses a simulation driven approach to investigate production tolerances and their effect on the NVH behavior of the EDU, using high precision transient multi-body dynamic analysis. This approach considers the main effects, influences, and the interaction from elastic structures of electric motor and transmission with accurate gear contact models in a fully coupled way. It serves as virtual end of line test, applicable in all steps of a new EDU development, by increasing
Klarin, BorislavSchweiger, ChristophResch, Thomas
Brake caliper rattle noise is difficult to simulate due to its non-stationary, random, and broadband frequency characteristics. Many CAE engineers have adopted rattle vibration as an alternative metric to quantitative noise levels. Previous rattle noise simulations primarily presented relative displacement results derived from normal mode analysis or vibration dB levels rather than actual noise dB levels. However, rattle noise consists of continuous impact noise, which must account for reflections, diffractions, and refractions caused by transient nonlinear contacts and localized vibrations—especially during extremely short contact events. To accurately simulate impact noise, vibration and acoustic characteristics should be analyzed using a simplified structure, given the numerous mechanisms influencing impact noise generation. The rattle noise can be effectively modeled using LS-Dyna, which incorporates both explicit and BEM solvers. The correlation between test results and CAE
Park, Joosang
This paper presents a comprehensive methodology for replicating and quantifying the clicking-noise phenomenon occurring between Generation 3-wheel hub bearings and Constant Velocity Joints (CVJ), particularly in electric vehicles (EVs) where quiet operation makes this noise more noticeable. The study focuses on characterizing the system through contact pressure and distribution measurements, alternating torque tests, and advanced NVH (Noise, Vibration, and Harshness) data processing. The methodology includes detailed descriptions of the physical phenomena, driving conditions generating the noise, and the specific test setup used to simulate real-world conditions. The NVH analysis make use of high-pass filtering techniques to isolate clicking-noise events from background noise, ensuring accurate identification and quantification. Candidate solutions are assessed based on their ability to mitigate clicking noise through the utilization of inherent system components. The results
Nardicchia, RiccardoMauro, Ivan
A research team led by scientists at Lawrence Berkeley National Laboratory (Berkeley Lab) has developed a new fabrication technique that could improve noise robustness in superconducting qubits, a key technology for enabling large-scale quantum computers.
The transportation and mobility industry trend toward electrification is rapidly evolving and in this specific scenario, wind noise aeroacoustics becomes one of the major concerns for OEMs, as new propulsion systems are notably quieter than traditional ones. There is, however, very limited references available in the literature regarding validation of computational fluid dynamics (CFD) simulations applied to the prediction of aeroacoustics contribution to the noise generated by large commercial trucks. Thus, in this work, high-fidelity CFD simulations are performed using lattice Boltzmann method (LBM), which uses very large eddy simulation (VLES) turbulence model and compared to on-road physical tests of a heavy-duty truck to validate the approach. Furthermore, the effect of realistic wind conditions is also analyzed. Two different truck configurations are considered: one with side mirror (Case A) and the other without (Case B) side mirrors. The main focus of this work is to assess the
Guleria, AbhishekNovacek, JustinIhi, RafaelFougere, NicolasDasarathan, Devaraj
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