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Assessment of Automotive Environmental Noise on Mobile Phone Hands Free Call Quality

FEV North America, Inc.-Jeffrey Pruetz, Channing Watson, Todd Tousignant, Kiran Govindswamy
  • Technical Paper
  • 2019-01-1597
To be published on 2019-06-05 by SAE International in United States
Environmental noises such as wind, road, powertrain, and HVAC are important aspects to consider when implementing a hands-free terminal for mobile phone calling. Traditionally these environmental noises have been exclusively considered for driver comfort, however, with the introduction of the hands-free terminals (HFT) and increasing consumer demand relative to mobile phone call quality, a broader implication of high background noise levels should be considered. HFT algorithm development and implementation can and does provide a high level of background noise suppression to mitigate these concerns, however, this is often done at the expense of computational power and cumulative delay during a phone call. A more advantageous solution would be to address the problem from a source and path perspective, however, this in itself is a challenging task and one that vehicle manufactures have and will continue to pursue as part of conventional vehicle development activities. The assessments shown throughout this paper establishes a sensitivity of HFT call quality to background noise levels, based on industry-standard metrics, including those defined by International Telecommunication Union (ITU) standards. This…
 

Towards a quiet vehicle cabin through digitalization of HVAC systems and subsystems aeroacoustics testing and design

Dassault Systemes SIMULIA-Vincent Vidal, Adrien Mann, Jonas Verriere, Minsuk Kim
Valeo Thermal Systems-Fabrice Ailloud, Manuel Henner, Olivier Cheriaux
  • Technical Paper
  • 2019-01-1476
To be published on 2019-06-05 by SAE International in United States
With the rise of electric autonomous vehicles, it has become clear that the cabin of tomorrow will drastically evolve to both improve ride experience and reduce energy consumption. In addition, autonomy will change the transportation paradigm, leading to a reinvention of the cabin seating layout which will add pressure on climate systems team to design quiet and energy efficient systems. Consequently, Heat and Ventilation Air Conditioning (HVAC) systems designers have to deliver products which performs acoustically better than before, but often with less development time. To success under such constraints, designers need access to methods providing both assessment of the system (or subsystems) acoustic performance, and identification of where the designs need to be improve to reduce noise levels. Such methods are often needed before a physical prototype is requested, and thus can only be achieved in a timely manner through digital testing. Previous studies have demonstrated the ability of a CFD/CAA approach based on the Lattice Boltzmann Method (LBM) to predict HVAC system noise including real and complex ducts, registers, mixing unit and blower…
 

Development of 1D model of impact force in powertrain equipment

Denso-Yuma Yoshimaru, Makoto Kondo, Yukie Omuro, Masashi Inaba
  • Technical Paper
  • 2019-01-1549
To be published on 2019-06-05 by SAE International in United States
Electromagnetic valves excellent in sealing properties and resistant to sliding are often used in powertrain equipment installed in gasoline- or diesel-engine vehicles. An electromagnetic valve has the function of moving internal valve members by means of electromagnetic force generated by the application of a voltage and thereby changing the flow path. When an electromagnetic valve operates, however, the valve members impact with one another, emitting impact noise caused by it. With the requirement for low noise in electromagnetic valves having become stricter recently from the viewpoint of comfort in the passenger compartment, predicting the noise is needed at the design stage. With this background, this paper describes the development of a 1D model of impact force that will enable the noise and the product performance to be examined simultaneously for a gasoline direct injection high-pressure pump. In contrast to the conventional model in which a movable member is taken as a mass point with a spring and a damper placed at the impact section, this paper proposes a technique in which a spring-mass model with…
 

Fast accurate non-destructive measurement of absorber impedance and absorption

3M-Jon Alexander
Bruel & Kjaer S&V Measurement A/S-Jason Kunio, Flemming Larsen
  • Technical Paper
  • 2019-01-1584
To be published on 2019-06-05 by SAE International in United States
Cabin acoustic comfort is a major contributor to the potential sales success of new aircraft, cars, trucks, and trains. Recent design challenges have included the increased use of composites, and the switch to electrically powered vehicles, each of which change the interior noise spectral content and level. The role of acoustic absorption in cabins is key to the optimisation of cabin acoustic comfort for modern vehicles, with acoustic impedance data needed in order to assess and optimise the impact of each component of a given lay-up. Measurements of absorbing interior trim are traditionally performed using either sample holder tests in a static impedance tube (impedance and absorption), or through tests in reverberation rooms (absorption only). Both of these procedures present challenges. In-tube absorption and impedance measurements are destructive, requiring highly accurate sample cutting and sealing. Reverberation room absorption measurements are subject to the effects of varying room diffusion, along with the impact of edge diffraction, sample geometry, and location. Finally, while non-destructive methods using hand-held probes also measure absorption, they are not able to measure…
 

Analyzing Field Environments to Understand Product Failure Causes

Vibration Research-Jade Vande Kamp
  • Technical Paper
  • 2019-01-1477
To be published on 2019-06-05 by SAE International in United States
Product failures often require expensive repairs or replacements. Over-engineering adds to recurring costs and its success is uncertain if the failure’s cause is not understood. Engineers need in-depth knowledge before attempting a re-design. This case study focuses on bus seat failures not predicted by industry standard tests. The goal was to collect comprehensive field vibration data and analyze that data to understand the failure’s cause. The study used accelerometers placed at various points in multiple seating configurations and across multiple field environments. Analysis identified transmissibility issues between axes of motion, as well as higher reliability seat configurations.
 

Comparison of Measurement Methods for Evaluating Displacement of Commercial Vehicle Seats

CVG-James Haylett
Univ of Washington-Peter Johnson
  • Technical Paper
  • 2019-01-1481
To be published on 2019-06-05 by SAE International in United States
Vehicle seats and seat suspension have been evolving ever since the introduction of seats with built-in, integral suspensions. Measuring the relative displacements of the seat suspension may help better understand the magnitude and frequency of displacements the seat suspension and ultimately the occupant is exposed to. These displacement measurements may complement acceleration measurements and may provide additional information to help improve vehicle seat design. Displacement can be measured directly with lasers and potentiometers, but it would be less complicated if accelerometers, already being used to measure and characterize the vehicle and vehicle seat vibration, could be used to measure the displacement. Accelerometers can produce relatively accurate, correlated displacement results from well behaved, controlled, sinusoidal cyclical vibrations, but their utility for measuring real-world random vibration needs further evaluation and characterization. This paper will compare gold-standard methods for measuring vertical seat displacements directly to displacements measured and derived by double integrating the vertical accelerations from accelerometers. Actual field displacement, acceleration and GPS measurements were collected from vehicles as they travelled over different road types. In this paper…
 

Vibro-acoustic transfer function measurement in vehicles using dodecahedral sound source and its application for material assessment

Mahindra & Mahindra Ltd-Kumar Tulesh, Samar Deshpande, Prasath R
Mahindra & Mahindra, Ltd.-Nitesh Anerao
  • Technical Paper
  • 2019-01-1532
To be published on 2019-06-05 by SAE International in United States
NVH is an important aspect of vehicle design since it is one of the highest priorities and biggest influencing factors for customer while making decision to buy a vehicle. Hence, automotive engineers strive to design the superior cabin compartment to maintain pleasant levels of noise, vibration and the overall experience within the vehicle. To quantify the amount of energy transmitted between source and receiver region, transfer function analysis is primarily used. The focus of this paper is to measure vibro-acoustic transfer function using reciprocity approach instead of direct impact test measurement. It is found that the vibro-acoustic reciprocity holds true even for non-linear system like vehicle. The reciprocal measurement involves usage of dodecahedral sound source to acoustically excite the cabin from desired seating location and accelerometers are placed at all the locations of interest on vehicle body. In case of direct measurement, vehicle body is excited using impact hammer and acoustic pressure is measured at desired seating location. It is observed that transfer function calculated with direct and reciprocal measurements showed a good match with…
 

The new challenges of NVH packages for BEVs

Autoneum Holding AG-Grégoire Lepoittevin, Jan Horak, Davide Caprioli
  • Technical Paper
  • 2019-01-1452
To be published on 2019-06-05 by SAE International in United States
Battery electric vehicles (BEVs) bring new challenge when it comes to develop their NVH package, which is affected by many new factors. The noise sources from the powertrain are different, for instance due to the presence of tonal components, strong harmonics and potential whining noise. Another important aspect is the missing effect of masking noise from a combustion engine. As a consequence, other noise sources, such as tires, become more predominant. This means that the NVH package has to be re-engineered considering the new noise sources ranking and cannot just be significantly decontented in general. In addition, the NVH package should at least partly counterbalance the vehicle weight increase due to the presence of a large and heavy battery pack in order to maximize the driving range. In the early days of BEVs, OEMs mostly carried over technologies used on combustion engine vehicles to electric cars. With the development growth of specific vehicle platforms for electric cars, NVH strategies and technologies might strongly change. First, this paper aims at providing a benchmarking review of current…
 

A Study on Control Logic Design for Power Seat

Hyundai Motor Co.-Misun Kwon, Taehoon Lee, Sangdo Park
  • Technical Paper
  • 2019-01-0466
To be published on 2019-04-02 by SAE International in United States
The large luxury sedan seat has a 22-way Movement. It offers a wide range of adjustments to enhance passenger comfort performance while it has many constraints on movement in constrained indoor space. In addition, the power seat is operated by a motor, which makes it difficult for the user to determine the amount of adjustment, unlike determining the amount of adjustment by the power and feel of a person, such as manual seat adjustment. IMS, one-touch mode, is also constrained by parameters such as indoor space package, user's lifestyle, etc. during function playback. This paper aims to design the seat control logic to achieve the best seat comfort while satisfying each constraint.The results of this study are as follows. Increase robustness of power seat control logic.Provide optimal adjustments and comfort at each location.Offer differentiated custom control and seating modes for each seat.Improve customer satisfaction and quality by upgrading software.
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Experimental PEM-Fuel Cell Range Extender System Operation and Parameter Influence Analysis

Vienna University of Technology-Johannes Höflinger, Peter Hofmann, Bernhard Geringer
  • Technical Paper
  • 2019-01-0378
To be published on 2019-04-02 by SAE International in United States
Fuel cells as alternative propulsion systems in vehicles can achieve higher driving ranges and shorter refueling times compared to pure battery-electric vehicles, while maintaining the local zero-emission status. However, to take advantage of pure battery electric driving, an externally rechargeable battery can be combined with a fuel cell range extender. As part of a research project, an efficient air supply system for a fuel cell range extender was developed. To this end, a 25 kW PEM fuel cell system test bench was set up. The different parameter influences of the test bench, in particular of the air supply system, were analyzed and evaluated in terms of stack/system efficiency and functionality. The control software of the test bench was specifically developed for the flexible operating parameter variation. All adjustable variables of the system (air ratio, stack temperature, pressure, etc.) were varied and evaluated at steady-state operating points. Likewise, the system was analyzed during dynamic operation and fault cases in adverse operating conditions (water condensation, oxygen deficiency) were identified. The system's warm-up process was also evaluated in…
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