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SAE 2015 Noise and Vibration Conference and Exhibition
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Current Status and Future Developments of ANC Systems

SAE International Journal of Passenger Cars - Mechanical Systems

Müller-BBM Active Sound Technology GmbH-Rolf Schirmacher
  • Journal Article
  • 2015-01-2223
Published 2015-06-15 by SAE International in United States
Active Noise Control (ANC) has long been seen as emerging technology. During recent years, however, it became popular in new vehicle and infotainment platforms within a broad range of OEMs. This paper summarizes the current status and lessons learned of production systems (as well as those entering production soon) and gives an outlook on how ANC and related technologies will integrate in future vehicles and audio/infotainment architectures.
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Computational Simulation to Validate Resonator through Bending Moment

Sharda Motor Industries Ltd. - R&D-Sivanandi Rajadurai, Guru Prasad Mani, Kavin Raja, Sundaravadivelu Mohan
Published 2015-06-15 by SAE International in United States
Bending moment is one of the strongest pursuits in resonator's structural validation. Eigen problems play a key role in the stability and forced vibration analysis of structures. This paper explains the methodology to determine the weak points in the resonator assembly considering the additional effects of the installation forces and temperature impacts. Using strain energy plots, weakest part of the product is identified in the initial stage.The solution comes in unique way of utilizing the worst case scenarios possible. As a consequence, the stress generated by these analyses will prove to be critical in concerning the durability issue of the system.These conditions are evaluated by a finite element model through linear approaches and results are summarized.
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Concept Phase Powertrain Development for NVH Using the Optimization Technique

Mahindra & Mahindra, Ltd.-Kodali Ajay Krishna, Pankaj Bhardwaj, Sanjeevgouda Patil, Mansinh Kumbhar
Published 2015-06-15 by SAE International in United States
One of the primary excitation sources in a passenger car comes from the powertrain [1]. Refinement of powertrain induced noise is the most critical tasks during a vehicle refinement. Due to ever increasing demand for reduced design and development cycle, most critical decisions have to be made at the concept stage. Powertrain radiated noise is one of the most important performance factor that must be evaluated during the concept stage. Solution time for calculating the radiated noise using the existing acoustic solvers is very high and requires very expensive resources like software and hardware. Arriving the optimal design with conventional method is very tedious job. A new method has been adopted for identifying the critical areas and coming up with the optimal design modifications within a short span of time. Powertrain radiated noise has been calculated with the help of acoustic solver. Topology optimization [2] is used at an early stage of the vehicle development process to arrive at a conceptual design proposal that is then fine-tuned for performance and manufacturability. This replaces time consuming,…
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Low-Frequency Noise Transfer Path Identification Study for Engine Sub-Frame Utilizing Numerical Simulation

R & D Center of SAIPA (AIRIC)-Sajjad Beigmoradi
Published 2015-06-15 by SAE International in United States
Nowadays, by the introduction of significant advances in automotive industries, noise, vibration and harshness (NVH), in the position of the main comfort attribute, plays a crucial role in marketing and passenger satisfaction. In order to cope NVH problems, three main actions are taken by NVH engineers for reducing perceived level of noise in cabin: Noise reduction in sources, Noise path treatment and Noise control at receiver. Among these approaches, those pertain to modification of noise pass, through structure and air, to the cabin are more prevalent in automotive applications. Accordingly, identification of noise paths that dominantly contribute to sound and vibration transfer to cabin phenomenon should be dealt with importance. In practice, engine vibration transmitted through sub-frame attachments to body can induce high level of noise and vibration to the passenger cabin. In this research, at first stage, optimization of shell thicknesses for four main engine sub-frame components is performed to minimize noise transfer function at driver's ear positions. Taguchi methodology is chosen for this matter as a robust method which reduces number of simulations…
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Powertrain Metric to Assess Engine Stop Start Refinement

FCA US LLC-Sudharsan Srinivasan, Jeff Orzechowski, Michael Schoenherr
Published 2015-06-15 by SAE International in United States
Every automaker is looking for ways to improve the fuel economy of its vehicle fleet to meet the EPA greenhouse gas regulation, which translates into 2025 Corporate Averaged Fuel Economy of 54.5 mpg. Engine Stop Start technology will improve the fuel economy of the vehicle by shutting down the engine when the vehicle is stationary. While this is an established technology in Europe, it is beginning to gain momentum in North America, where NVH refinement is a stronger consideration. To utilize the fuel economy benefits of Stop Start technology in the North American market, the technology must be seamlessly incorporated into the vehicle.This paper gives an overview of characterizing an auto start based on the features of a few Powertrain-system-level metrics. Following the fundamentals of NVH, (Source, Path and Receiver) the receiver touch points will be less perceptible to vibration, if the powertrain-system source is made smoother. Tangential components, which are functions of cylinder pressure and crank angle, are the dominant forces during auto start. Six powertrain-system-level metrics that will define an auto start are…
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Geartrain Noise Optimization in an Electrical Drive Unit

American Axle & Mfg Inc.-Zhaohui Sun, Glen Steyer, Jason Ley
Published 2015-06-15 by SAE International in United States
Alternative powertrains, in particular electric and plug-in hybrids, create a wide range of unique and challenging NVH (noise, vibration & harshness) issues in today's automotive industry. Among the emerging engineering challenges from these powertrains, their acoustic performances become more complicated, partially due to reduced ambient masking noise level and light weight structure. In addition, the move away from conventional displacement engines to electrical drive units (EDU) has created a new array of NVH concerns and dynamics, which are relatively unknown as compared to the aforementioned traditional setups.In this paper, an NVH optimization study will be presented, focusing on four distinct factors in electric drive unit gear mesh source generation and radiation: EDU housing and bearing dynamics, gear geometry, EDU shafting torsional dynamics, and EDU housing structure. The study involves intensive FEA modeling/analyses jointly with physical validation tests. All four factors are evaluated for their contributions to noise performance, as well as their theoretical performance boundaries. Results are presented, which demonstrate the ability of this engineering approach to both optimize mass and performance of EDU products.
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Side Mirror Noise with Adaptive Spectral Reconstruction

NUMECA International-Charles Hirsch, Piergiorgio Ferrante
NUMECA Japan-Katsutomo Isono
Published 2015-06-15 by SAE International in United States
A new method called Adaptive Spectral Reconstruction (ASR) for the stochastic reconstruction of broadband aeroacoustic sources starting from steady CFD analyses is presented and applied to the evaluation of the noise radiated by a model automotive side mirror.The new approach exploits some ideas from both SNGR and RPM, and for some aspects can be considered as a sort of mixing between the two methods since it permits to reconstruct both the frequency content of the turbulent field (as done by SNGR) and the spatial cross correlation (as done by RPM).The turbulent field is reconstructed with a sum of convected plane waves, but two substantial differences are introduced in respect of SNGR. The first difference concerns the spatial variation of the parameters that define each wave, that depends on the wavelength of each wave, rather than being kept constant or related to the CFD correlation length. The second innovative aspect is the usage of a dedicated full hexa adaptive mesh that is refined in function of the expected local correlation length, ensuring that the mesh be…
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A Case Study: Application of Analytical and Numerical Techniques to Squeak and Rattle Analysis of a Door Assembly

Hyundai Motor Co.-Ki-Chang Kim, Sang-Woo Lee, Seok-Gil Hong
University of Cincinnati-Jay Kim, Gil-Jun Lee
Published 2015-06-15 by SAE International in United States
Squeak and rattle (S&R) problems in body structure and trim parts have become serious issues for automakers because of their influence on the initial quality perception of consumers. In this study, various CAE and experimental methods developed by Hyundai Motors for squeak and rattle analysis of door systems are reported. Friction-induced vibration and noise generation mechanisms of a door system are studied by an intelligent combination of experimental and numerical methods. It is shown that the effect of degradation of plastics used in door trims can be estimated by a numerical model using the properties obtained experimentally. Effects of changes in material properties such as Young's modulus and loss factor due to the material degradation as well as statistical variations are predicted for several door system configurations. As a new concept, the rattle and squeak index is proposed, which can be used to guide the design. The predicted S&R of the door system from the CAE process were compared with experimental results. Practical applications of the developed process and possible future directions of CAE based…
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Perception of Diesel Engine Gear Rattle Noise

SAE International Journal of Passenger Cars - Mechanical Systems

Cummins Inc.-Frank Eberhardt
Purdue University-Brandon Sobecki, Patricia Davies, J Stuart Bolton
  • Journal Article
  • 2015-01-2333
Published 2015-06-15 by SAE International in United States
Component sound quality is an important factor in the design of competitive diesel engines. One component noise that causes complaints is the gear rattle that originates in the front-of-engine gear train which drives the fuel pump and other accessories. The rattle is caused by repeated tooth impacts resulting from fluctuations in differential torsional acceleration of the driving gears. These impacts generate a broadband, impulsive noise that is often perceived as annoying. In most previous work, the overall sound quality of diesel engines has been considered without specifically focusing on predicting the perception of gear rattle. Gear rattle level has been quantified based on angular acceleration measurements, but those measurements can be difficult to perform. Here, the emphasis was on developing a metric based on subjective testing of the perception of gear rattle. In the first part of the present work, a method to simulate gear rattle noise and incorporate it into a no-gear-rattle (baseline) recording was developed. That procedure enabled controlled variation of rattle within the total engine noise signal. The simulations were then used…
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Optimization of EV Mounting System Considering Power Train Torsion Control

Tongji University-Peng Yu, Tong Zhang, Jing Li, Shiyang Chen, Rong Guo
Published 2015-06-15 by SAE International in United States
Faced on transient vibration of EV, considering the characteristics of the electric drive system, active and passive integrated transient vibration control method of power train mounting system was proposed.Models of power train system and mounting system were established, modal characteristics were grasped by simulation and experiment. A feed-forward controller was constructed from the facet of active control, mounting system transient vibration and power train torsion vibration were reduced. Based on this, further optimization of mounting system was conducted from a passive control perspective.Results show that the active and passive integrated control method can effectively reduce the dynamic reaction force of mounting points, improve the vibration conditions of power train and vehicle body as well.
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