The SAE MOBILUS platform will continue to be accessible and populated with high quality technical content during the coronavirus (COVID-19) pandemic. x

Your Selections

Noise, Vibration, and Harshness (NVH)
Acoustics
Harshness
Noise
Exterior noise
Interior noise
Noise measurement
Noise, vibration, and harshness standards and regulations
Sound quality
Vibration
Show Only

Collections

File Formats

Content Types

Dates

Sectors

Topics

Authors

Publishers

Affiliations

Committees

Events

Magazine

Series

   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Reduction of the Effect of the Creep Groan Brake Excitation in a Comercial Vehicle

IDIADA Automotive Technology SA-Angel Sanchez
  • Technical Paper
  • 2020-01-1530
To be published on 2020-06-03 by SAE International in United States
One of the results generated by the stick-slip intermittent motion of a brake at the friction interface is the Creep Groan Noise which is a low frequency self-excited vibration, normally less than 220 Hz. This local vibration generated between the brake couple, is transmitted through the suspension system until the passengers of the vehicle in form of vibration and noise. This paper presents a methodology that combines testing and numerical models in order to 1) detect the source of the Creep Groan, 2) create a correlated numerical model and 3) produce countermeasures that reduce the amplitude of the noise at occupant positions. The vehicle under investigation was a commercial vehicle employing air-actuated brake drums. From testing, global vehicles modes and displacements under operational conditions were respectively investigated by means of Operational Deflection Shapes and Real Time Animation. These techniques allowed to prove the existence of a feedback loop with a positive gain that excites a suspension resonance mode, creating an unstable shaking effect in the whole vehicle. In-service data suggest that the brake actuation system…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

A Diagnostic Technology of Powertrain Parts that Cause Abnormal Noises using Artificial Intelligence

Hanyang University-Kyoungjin Noh, Joon-Hyuk Chang
Hyundai Motor Company-Insoo Jung, Dongchul Lee, Dongkyu Yoo, Kibeen Lim
  • Technical Paper
  • 2020-01-1565
To be published on 2020-06-03 by SAE International in United States
In general, when a problem occurs in a component, various phenomena appear, and abnormal noise is one of them. The service technicians diagnose the noise through the analysis using hearing and equipment. Depending on their experiences, the analysis time and diagnosis accuracy vary widely. The newly developed AI-based diagnostic technology diagnoses parts that cause abnormal noises within seconds when a noise is input to the equipment. To create a learning model for diagnosis, we collected as many abnormal noises as possible from various parts, and selected good and bad data. This process is very important in the development of diagnostic techniques. Artificial intelligence was learned by deep learning with selected good data. This paper is about the technology that can diagnose the abnormal noises generated from the engine, transmission, drivetrain and PE (Power Electric) parts of the eco-friendly vehicle through the diagnosis model composed of various methods of deep learning.
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

High Speed Camera Based 3D Experimental Modal Analysis

University of Ljubljana-Domen Gorjup, Janko Slavic, Miha Boltezar
  • Technical Paper
  • 2020-01-1569
To be published on 2020-06-03 by SAE International in United States
High-speed camera systems in vibration measurements are typically limited to identifying motion perpendicular to the optical axis. Depth information, lost in the imaging process, can be recovered by using the recently introduced frequency domain triangulation and consequently full 3D deflection shapes can be obtained. This research presents the required theoretical background where the multiview image data is used for spatial small harmonic motion identification. Vibrations of an arbitrary-shaped specimen can be identified in the frequency domain using only a single, moving high-speed camera, extending the field-of-view of the established image-based vibration measurement methods. Real test cases are also presented.
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Development of the Active Sound Generation Technology using Motor Driven Power Steering System

Hyundai Motor Co.-Kyoung-Jin Chang
Mdynamix AG-Leonhard Angerpointner, Dominik Schubert, Matthias Niegl
  • Technical Paper
  • 2020-01-1536
To be published on 2020-06-03 by SAE International in United States
As original engine sound is usually not enough to satisfy the driver’s desire for the sporty and fascinating sound, active noise control (ANC) and active sound design (ASD) have been great technologies in automobiles for a long time. However, these technologies which enhance the sound of vehicle using loud speakers or electromagnetic actuators etc. lead to the increase of cost and weight due to the use of external amplifier or external actuators. This paper presents a new technology of generating a target sound by the active control of a permanent magnet synchronous motor (PMSM) which is already mounted in vehicle. Firstly, an algorithm of this technology, called an active sound generation (ASG), is introduced with those signal conversion process, and then the high frequency noise issue and its countermeasure are presented. Secondly, ASG test bench is designed using a motor driven power steering (MDPS) system and then it is checked if ASG has any influence on an original function of MDPS. Thirdly, motor-induced vibration is measured in the transfer path and then the appropriate level…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

How Can Active Exhaust Systems Contribute to the Reduction of CO2 Emission and Comply with Future Pass-by Noise Limits?

Eberspaecher Exhaust Technology GmbH-Jan Krueger, Peter Wink, Maike Werner
  • Technical Paper
  • 2020-01-1534
To be published on 2020-06-03 by SAE International in United States
The pass-by noise limits of passenger vehicles according to ISO 362 / R51.3 will be further reduced by 2 dB in 2024 in Europe. Since the pass-by noise is substantially influenced by exhaust noise, the effort for the exhaust system needs to be increased. This results in systems with larger mufflers or higher backpressure. However, the more stringent CO2-emission targets require ever more efficient powertrains, which calls for rather lower backpressure to optimize the engine design. This paper describes, how compact active exhaust lines can support a design for low backpressure and high acoustic attenuation at the same time. For two passenger vehicle with gasoline engines, active exhaust lines are investigated in detail and the results are compared to the series production exhaust lines. Thus, in one exemplary case, the pass-by noise of a limousine could be reduced from 70 dB(A) to 68 dB(A) without any change in the vehicle design except the improved exhaust system.
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Development, System Integration and Experimental Investigation of an Active HVAC Noise Control System for a Passenger Car

Fraunhofer Institute LBF-Jonathan Millitzer, Valentin Mees, Christopher Ranisch
Hyundai Motor Company-Joong-Kwan Kim, Jinmo Lee, ChiSung Oh, Kang-Duck Ih
  • Technical Paper
  • 2020-01-1538
To be published on 2020-06-03 by SAE International in United States
Current developments in the automotive industry such as electrification and consistent lightweight construction increasingly enable the application of active control systems for the further reduction of noise in vehicles. As different stochastic noise sources such as rolling and wind noise as well as noise radiated by the ventilation system are becoming more noticeable and as passive measures for NVH optimization tend to be heavy and construction space intensive, current research activities focus on the active reduction of noise caused by the latter mentioned sources. This paper illustrates the development, implementation and experimental investigation of an active noise control system integrated into the ventilation duct system of a passenger car. Making use of a model-based design process, the development is based upon a holistic numerical simulation model integrating a reduced order acoustic model derived from finite element simulations as well as simplified loudspeaker and microphone characteristics. The numerical simulation assists the selection of a suitable loudspeaker microphone configuration, taking into account the available installation space and the integration of low-cost loudspeakers and MEMS microphones. The ventilation…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Efficient Modeling and Simulation of the Transverse Isotropic Stiffness and Damping Properties of Laminate Structures using the Finite Element Method

BMW Group-Vlad Somesan, Endre Barti
Fraunhofer Lbf-Thilo Bein
  • Technical Paper
  • 2020-01-1573
To be published on 2020-06-03 by SAE International in United States
The Noise Vibration and Harshness (NVH) characteristics and requirements of vehicles are changing as the automotive manufacturers turn their focus from developing and producing cars propelled by internal combustion engines (ICE) to electrified vehicles. This new strategic orientation enables them to offer products that are more efficient and environmentally friendly. Although electric powertrains have many advantages compared to their established predecessors they also produce new challenges that make it more difficult to match the new requirements especially regarding NVH. Electric motors are one of the most important sources of vibrations in electric vehicles. In order to address the new challenges in developing powertrains that match the acoustic comfort requirements of the customers and also shape the development process as efficiently as possible, car manufacturers use numerical simulation methods to identify NVH problems as early in the design process as possible. Numerically describing the dynamic properties of electric motor components such as the stator or rotor is proving to be especially difficult as they contain heterogeneous parts that have viscoelastic orthotropic or transverse isotropic stiffness and…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Advance CAE Methods for NVH Development of High Speed Electric Axle

AVL LIST GmbH-Mehdi Mehrgou, Julian Pohn, Bernhard Graf, Christoph Priestner
AVL Software and Functions Gmbh-Mathias Deiml
  • Technical Paper
  • 2020-01-1501
To be published on 2020-06-03 by SAE International in United States
By developing more electric vehicles more and more focus are to the noise and vibration from Electric Drive unit. Here a high-speed E-axle for premium class vehicle is being developed up to 30,000 rpm, with high power density and lightweight design which introduce new challenges. Benchmarking of different E-axle and vehicles lead to targets which can be used at the begin of development as subsystem targets. This paper shows first how these targets like tonal noise can be simulated. Then the CAE method is used to optimize the source and structure to improve the NVH. Different aspects like torque ripple, electric whine, gears whine and mounting are discussed.
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

CAE Support to Vehicle Audio Installation Issues

Volvo Car Corporation-Andrzej Pietrzyk
  • Technical Paper
  • 2020-01-1575
To be published on 2020-06-03 by SAE International in United States
Audio CAE is an emerging area of interest for a vehicle OEM, despite the fact that the development of the audio system is often left to a specialized supplier. Especially the questions regarding early stages of the vehicle design, like choosing the possible positions for speakers, deciding the installation details that can influence the visual design, and integration of the low frequency speakers with the body & closures structure, are of interest. Therefore, at VCC, the development of the CAE methodology for audio applications has been undertaken. The long term goal is to enable performing subjective evaluation of sound in a virtual car, and integrating audio evaluation in the NVH simulator. The key to all CAE applications is the loudspeaker model made available in the vibro-acoustic software used within the company. Such a model has been developed, implemented and verified in different frequency ranges and different applications. The applications can be divided into the low frequency ones (concerning the installation of woofers and subwoofers), and the middle/high frequency ones (concerning the installation of midrange and…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Robust Development of Electric Powertrain NVH for Compact Electric SUV

Hyundai Motor Company-Tae-Won Ha, Jin-Wook Huh, Sang-Kyu Choi, Dong-Wook Min, Chang-Kook Chae
Romax Technology-Annabel Abdy, Carsten Schmitt, Hanafy Mahmoud, Sharad Jain, Leon Rodrigues
  • Technical Paper
  • 2020-01-1503
To be published on 2020-06-03 by SAE International in United States
Electric vehicles (EV's) present new challenges to achieving the required noise, vibration & harshness performance (NVH) compared with conventional vehicles. Specifically, high-frequency noise and abnormal noise, previously masked by the internal combustion engine can also cause annoyance in an EV. Electric motor (E-motor) whine noise caused by electromagnetic excitation during E-motor operation is caused by torque ripple and stator local excitation. Under high speed and high load operating conditions, the sound level is low, however high frequency whine noise is a factor that can impair the vehicle level NVH performance. An example of a previously masked abnormal noise is a droning noise that can be caused by manufacturing quality variation of the spline coupling between the rotor shaft of the E-motor and the input shaft of the reducer, it is dominated by multiple higher orders of the E-motor rotation frequency. In this study, the high speed and high load condition whine noise problem was reproduced through electromagnetic and structural analysis, and the countermeasure (E-motor geometry refinements to reduce the excitations and mechanical system transfer path…