Automotive aeroacoustics: An overview (original) (raw)
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Improving vehicle aeroacoustics using machine learning
This paper presents a new approach to improving the overall aeroacoustic comfort of a vehicle, an important feature of vehicle design. The traditional improvement process is extended to benefit extensively from machine learning, information retrieval and information extraction technologies to assist the wind tunnel engineers with difficult tasks. The paper first describes the general approach and then focuses on providing detailed descriptions of the two most important tasks. One task is an assessment of the degree of discomfort for a human caused by wind noise in a vehicle, when the noise spectrum is known. Another task is to find standard vehicle components that would, if added to the vehicle, affect the noise spectrum in a way so as to alleviate the human's discomfort. The results of the end user evaluation of the entire system are also presented to reflect the strengths of this approach.
A hierarchical approach is first presented to analyse the variability of structure-borne interior noise levels. A new terminology is proposed to clearly distinguish between intra variability, inter variability and measurement uncertainty. The hierarchical approach has been applied to experimentally determine the intra variability of booming noise on the same vehicle due to variations of the environmental conditions. The booming noise at several locations inside the vehicle was measured as well as the vibrations of the engine, the dynamic stiffness of the engine mounts and a structural acoustic transfer function of the body. Interior noise level at the driver's ear shows measured intra variability level between 2 and 20 dB depending on the engine speed. The inter variability of booming noise was also measured: it turns out that its level is lower than the intra variability one. © 2007 Institute of Noise Control Engineering.
Index for vehicle acoustical comfort inside a passenger car
Applied Acoustics, 2008
Sound quality is among the main factors that influence customers' preference for choosing good automobile products. It all started more than 10 years ago and grows up so fast due to high competition in the automotive industries. A-weighted noise levels and sound power are usually utilised to measure the noise but they are not adequate to characterise the impact sound inside a car. The most popular approach to determine sound quality of a product is to define an annoyance or specific index, which involves both subjective and objective evaluations. Subjective and objective tests should be studied concurrently in order to determine the sound quality inside a passenger car. This approach is used in this paper to evaluate vehicle comfort index according to most frequently used sound quality metrics, namely; Zwicker loudness, sharpness, roughness and fluctuation strength. As a result researchers of different fields of automotive acoustics investigations can use this index according to the type of road (international road roughness) without any need to perform time-consuming jury tests. The metrics are correlated with jury test results that show which of them and how much has affected the acoustical comfort of the vehicle. The relation between road roughness and vehicle acoustical comfort index is another point of interest in this research.
Prediction of Cabin Noise inside passenger cars: the Airborne Noise Project
The Airborne Noise Project is a methodology for setting the sound packages target and related the cost/benefit for new cars for future improvements. The initial goal is the definition of the possibility to simulate the P/P transfer function for different sources. This method will be useful at the end of the project to define weight of different packages, targets and possible inefficiencies of others particular in the car (leaks, flanking paths). The combination of different targets like leaks, sound isolation, absorption, flanking paths and their weight in the passenger compartment can be the starting point to define possible improvements in the quality of the car.
SAE International Journal of Passenger Cars - Mechanical Systems, 2014
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Aeroacoustics Investigation of an Automotive Exhaust Muffler
Advanced Materials Research, 2014
Traffic is a major source of environmental noise in modern society. Subsequently, the development of new vehicles is subjected to heavy governmental legislations. The major noise source on common road vehicles during acceleration is the flow noise caused by turbulent exhaust gas. The main goal of this work is to develop an appropriate Aeroacoustic simulation method to investigate the acoustic of sound on exhaust automotive muffler. The range of validity of the method is studied comparing results to experimental data. The Computational Aeroacoustics (CAA) results are compared with an experimental test in a vehicle during its acceleration and the mean flow model of the muffler has a satisfactory mesh with a suitable inlet boundary provided by an engine dynamometer data. The present work describes a good agreement between computational and experimental approach for the Aeroacoustics behavior of a specific configuration of exhaust muffler.
Sound signature of Quiet Vehicles : state of the art and experience feedbacks
2013
It seems now widely conceded that Quiet Vehicles are actually too quiet for leaving out the crucial question of their sound signature. When considering the increasing volume of works in that domain, it looks obvious that a dedicated sound design approach for these new means of transport becomes fully relevant regarding security (for people around) or ergonomics (for people inside). For quite a long time, and among other labs, the Sound Perception and Design (SPD) team at Ircam has focused a part of its works on that topic which represents an emblematic framework to operate knowledge, methodologies or tools developed in the field of Sonic Interaction Design. The paper aims at presenting, first, an overview of recent scientific studies in that field together with a review of current legislations or standards that are – or tend to be – effective in several countries. In a second part, we will try to adress this issue in the light of several works achieved within SPD team, especially so...
HVAC noise perception in car cabin: a preliminary comparison between ICEVs and HEVs
Proceedings of the ICA congress, 2019
Noise in car cabins is a key aspect of the drivers/passengers' comfort experience. It is produced by the aerodynamic interactions of the vehicle and the rolling, by the engine and all the auxiliary systems installed in the engine compartment. Although cars manufacturers focused their efforts to reduce the noise transmission inside the cabin, for Internal Combustion Engine vehicles (ICEVs) the mainly noise source is still the engine noise. Nevertheless, with the advent of hybrid/full electric vehicles (HEVs) in the automotive industry, the engine noise has been reduced dramatically, especially at low rpm, leaving emerging the noise of auxiliary sources. One of them is the air conditioning noise. Although doesn't exist a consolidated model to describe HVAC noise perception inside the vehicles, the paper intends to explore the expected changes of the drivers/passengers' auditory perception from ICEVs to HEVs. The acoustic and psychoacoustic metrics of different binaural recordings, carried out inside ICEVs and HEVs, are showed and compared.
Prominence of tones in electric vehicle interior noise
2013
The rapid increase of various types of electric vehicles introduced creates new challenges also in respect to noise control and sound quality. With the absence of acoustic emissions from an operating internal combustion engine, the presence of high pitched tonal components from the electric traction motor can be pronounced in many driving conditions. In order to fulfill the customer's expectations of interior acoustic comfort, further knowledge needs to be gained about the perception of tonal components appearing in a mix of random noise from wind and tires. This paper presents a study on the relationship between the psychoacoustic metric prominence ratio (PR) and the threshold of detecting the tones and also the perceived annoyance for both constant speed and acceleration in a pure electric vehicle. The listening test results reveal that below 800 Hz, a higher PR value is required for audibility compared to tones above 2.5 kHz. For all driving conditions, the perceived annoyance was relatively low with small differences between the frequency ranges for the low audibility stimuli (PR≤2 dB). With higher audibility (PR≥3 dB), the perceived annoyance was significantly increased for frequencies above 5 kHz compared to frequencies below 800 Hz for the constant speed cases. The acceleration cases yielded similar conclusions. The findings are intended to support in the requirement specification process for sounds in electric vehicles.