The Vehicle Noise Control Engineering Academy covers a variety of vehicle noise control engineering principles and practices. There are two concurrent, specialty tracks (with some common sessions): Powertrain Noise and Vehicle Interior Noise. Participants should choose and register for the appropriate Academy they wish to attend. The Powertrain Noise track focuses on noise and vibration control issues associated with internal combustion, hybrid and electric powered vehicles. The vehicle in this case includes passenger cars, SUVs, light trucks, off-highway vehicles, and heavy trucks.
The Vehicle Noise Control Engineering Academy covers a variety of vehicle noise control engineering principles and practices. There are two concurrent, specialty tracks (with some common sessions): Vehicle Interior Noise and Powertrain Noise. Participants should choose and register for the appropriate track they wish to attend. The Vehicle Interior Noise track focuses on understanding the characteristics of noise produced by different propulsion systems, including internal combustion, hybrid and electric powered vehicles and how these noises affect the sound quality of a vehicle’s interior.
Due to their remarkable efficiency and efficacy, chevrons have emerged as a prominent subject of investigation within the Aviation Industry, primarily aimed at mitigating aircraft noise levels and achieving a quieter airborne experience. Extensive research has identified the engine as the primary source of noise in aircraft, prompting the implementation of chevrons within the engine nozzle. These chevrons function by inducing streamwise vortices into the shear layer, thereby augmenting the mixing process and resulting in a noteworthy reduction of low-frequency noise emissions. Our paper aims to conduct a comparative computational analysis encompassing seven distinct chevron designs and a design without chevrons. The size and configuration of the chevrons with the jet engine nacelle were designed to match the nozzle diameter of 100.48mm and 56.76mm, utilizing the advanced SolidWorks CAD modeling software.
Electromechanical Power Contactors are widely used in the Power Distribution units of large commercial & military aircrafts to control the different power sources. In aerospace applications the SWaP (size, weight, and power consumption) is very important since the available space is limited, the weight contributes to higher fuel consumption along with the requirement of high-power electrical sources for catering the high-power requirements. Since more than 100 contactors are used in a single aircraft even a small saving in SWaP leads to huge benefits. Managing the SWaP constraints along with the Harsh environmental and thermal requirements associated with Aerospace applications is a major bottleneck for futuristic aerospace transportation.
In this paper, we propose a novel Split Ring Resonator (SRR) metamaterial capable of achieving a total bandgap in the material’s band structure, thereby reflecting air-borne and structure-borne noise in a targeted frequency range. Electric Vehicles (EVs) experience tonal excitation arising from the switching frequencies associated with motors and inverters, which affects occupant perception of vehicle quality. Recently proposed metamaterial designs isolate either air-borne noise or structure-borne noise, but not both. To achieve isolation of both air-borne and structure-borne acoustic energy associated with these tonal frequencies, we propose a metamaterial supercell with transverse and longitudinal resonant frequencies falling in the desired bandwidth of the total bandgap. We calculate the resonant frequencies and corresponding mode shapes using Finite Element (FE) modal analysis.
The China Automotive Technology and Research Center (CATARC) has completed two new wind tunnels at its test center in Tianjin, China: an aerodynamic/aeroacoustic wind tunnel (AAWT), and a climatic wind tunnel (CWT). The AAWT incorporates design features to provide both a very low fan power requirement, 3.1 MW at 250 km/hr with a 28 m2 test section, and a very low background noise, 58.2 dB(A) at 150 km/h, putting it amongst the quietest in the automotive world. These features are also combined with high flow quality, a full boundary layer control system and 5-belt rolling road (producing a 5 mm block height boundary layer profile), an automated traversing system, and a complete acoustic measurement system including a 3-sided microphone array. The CWT, located in the same building as the AAWT, has a flexible nozzle to deliver 250 km/h with an 8.25 m2 nozzle, and 130 km/h with a 13.2 m2 nozzle.
As a key component of in-vehicle intelligent voice technology, speech enhancement can extract clean speech signals contaminated by environmental noise to improve the quality and intelligibility of speech perception. It has broad applications in human-vehicle interaction, in-car communication, and in-car cinema. Although some end-to-end time-domain-based speech enhancement methods have been proposed, few models are designed based on the characteristics of speech signals. In this paper, we propose a new U-Net based speech enhancement method that utilizes the temporal correlation of speech signals to reconstruct higher-quality and more intelligible clean speech.
As the mobility becomes complex, the coopertion of test and simulation is more and more important. For several years, various technologies for hybrid methods of test and simulation, such as VPT, FBS decoupling, modal model, SEMM and auralization have been studied and developed to help virtual development activities. As a result, the model based roadnoise development process and dedicated softwares have been developed. In this study, the system models such as tire blocked force, suspension FRFs and body FRFs were made by experiment and simulation and assembled to predict vehicle’s roadnoise. As a objective evaluation, roadnoise was analysed and the systematic TPA and sensitivity analysis process and program were development to set reasonable system targets to meet vehicle target. Then, as a subjective evaluation, roadnoise were auralized for various driving conditions such as speeds and road types according to driver’s input.
In vehicle development, reducing noise is a major concern to ensure passenger comfort. As electric vehicles become more common and engine and vibration noises improve, the aerodynamic noise generated around the vehicle becomes relatively more noticeable. In particular, the fluctuating wind noise, which is affected by turbulence in the atmosphere, gusts of wind, and wake caused by the vehicle in front, can make passengers feel uncomfortable. However, the cause of the fluctuating wind noise has not been fully understood, and a solution has not yet been found. The reason for this is that fluctuating wind noise cannot be quantitatively evaluated using common noise evaluation methods such as FFT and STFT. In addition, previous studies have relied on road tests, which do not provide reproducible conditions due to changing atmospheric conditions. To address this issue, automobile manufacturers are developing devices to generate turbulence in wind tunnels.
In recent years, with the development of computing infrastructure and methods, the potential of numerical methods to reasonably predict aerodynamic noise in compressors has increased. However, aerodynamic acoustic modeling of complex geometries and flow systems is currently immature, mainly due to the greater challenges in accurately characterizing turbulent viscous flows. Therefore, recent advances in aerodynamic noise calculations for automotive turbocharger compressors were reviewed and a quantitative study of the effects for turbulence modeling (Shear-Stress Transport (SST) and Detached Eddy Simulation (DES)) and time-steps (2°and 4°) in numerical simulations on the performance and acoustic prediction of a compressor under full operating conditions was investigated. The results showed that for the compressor performance, the turbulence models and time-step parameters selection were within 1.5% error of the simulated and measured values for pressure ratio and efficiency.
In the process of automobile industrialization, integrated electric drive systems turn to be the mainstream transmission system of electric vehicles gradually. The main sources of noise and vibration in the chassis are from the gear reducer and motor system, as a replacement of engine. For improving the electric vehicles NVH performance, effective identification and quantitative analysis of the main noise sources are a significant basis. Based on the rotating hub test platform in the semi-anechoic chamber, in this experiment, an electric vehicle equipped with a three-in-one electric drive system is taken as the research object. As well the noise and vibration signals in the interior vehicle and the near field of the electric drive system are collected under the operating conditions of uniform speed, acceleration speed, and coasting with gears under different loads, and the test results are processed and analyzed by using the spectral analysis and order analysis theories.
This paper analyzes the mechanism of vibrational energy propagation and panel vibration generation at the point joints between frame and panel which can be applied to reduce the vehicle interior noise. In this study, we focused on the traveling wave in the early stage of propagation before the mode is formed, and investigated the mechanism of panel vibration generation due to wave energy propagation and its reduction method. First, we show theoretically that the out-of-plane component of the transmitted power at the point junction between frame and panel that contributes to panel vibration is associated with frame deformation. Then, we show through numerical verification that panel vibration can be reduced by reducing the transferred power of the out-of-plane component, and explain the effectiveness of the frame-to-panel joint design guidelines based on energy propagation analysis. Next, This analysis technique is applied to the vehicle body model.
During the pure electric vehicle high speed cruise driving condition, the unsteady air flow in the chassis cavity is susceptible to self-sustaining oscillations phenomenon. And the aerodynamic oscillation excitation could be coupled with the cabin interior acoustic mode through the body pressure relief valve, the low frequency booming noise may occur and seriously reduces the driving comfort. This paper systematically introduces the characteristics identification and the troubleshooting process of the low frequency aerodynamic noise case. Firstly, combined with the characteristics of the subjective jury evaluation and objective measurement, the acoustic wind tunnel test restores the cabin booming phenomenon. The specific test procedure is proposed to separate the noise excitation source.