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Numerical Investigation of Tonal Noise at Automotive Side Mirrors Due to Aeroacoustic Feedback

Daimler AG-Alexander Schell, Mark Eiselt
  • Technical Paper
  • 2020-01-1514
To be published on 2020-06-03 by SAE International in United States
In addition to the typical broadband noise character of wind noise, tonal noise phenomena can be much more disruptive, regardless of the overall interior noise quality of the vehicle. Whistling sounds usually occur by flow over sharp edges and resonant gaps, but can also be caused by the feedback of sound waves with laminar boundary layers or separation bubbles and the resulting frequency-selective growth of boundary layer instabilities. Such aeroacoustic feedback can e.g. occur at the side mirror of a vehicle and one compellingly needs the coupling of acoustic and flow field. A compressible large eddy simulation (LES) is in principle suitable but one has to take care of any numerical artifacts which can disturb the entire acoustic field. This paper describes the possibility to resolve aeroacoustic feedback with a commercial 2nd/3rd order finite volume CFD code. A zonal RANS/LES approach is used to ensure a realistic flow around the exterior side mirror mounted at a Mercedes-Benz C-Class. The provided compressible LES are using non-reflecting boundary conditions in combination with a sponge zone approach to…
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A Research on Kinematic Optimization of Auto Flush Door Handle System

Hyundai Motor Group-Jungho Han, Kyoungtaek Kwak, Jinwoo Nam, Oktae Jung, Jinsang Chung
  • Technical Paper
  • 2020-01-0623
To be published on 2020-04-14 by SAE International in United States
A fascinating exterior appearance is one of the most important values for customers so the realization of the innovative styling has been a major topic for car makers for several years. Also, since the base of autonomous driving and electric vehicle is being expanded recently, it is essential to not only create high-tech image on a vehicle but also realize the engineering design in reality. From that point of view, the auto flush handle can be unique sales point to enhance the degree of the completion of the exterior styling. The purpose of this study is to establish the kinematic system of auto flush door handle to overcome the exterior handicaps such as not only the excessive exposure of the internal area on the deployed position but also to determine the proper operating speed. In order to resolve these issues, the Scott-Russell mechanism is applied to the auto flush handle system. The mechanism is applied to realize the straight motion so exterior quality can be improved to minimize inner gap and prevent link exposure. In…
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Decision Making and Trajectory Planning of Intelligent Vehicle’ s Lane-Changing Behavior on Highways under Multi-Objective Constrains

Wuhan University of Technology-Linzhen Nie, Zhishuai Yin, Haoran Huang
  • Technical Paper
  • 2020-01-0124
To be published on 2020-04-14 by SAE International in United States
Discretionary lane changing is commonly seen in highway driving. Intelligent vehicles are expected to change lanes discretionarily for better driving experience and higher traffic efficiency. This study proposed to optimize the decision-making and trajectory-planning process so that intelligent vehicles made lane changes not only with driving safety taken into account, but also with the goal to improve driving comfort as well as to meet the driver’ s expectation. The mechanism of how various factors contribute to the driver’s intention to change lanes was studied by carrying out a series of driving simulation experiments, and a Lane-Changing Intention Generation (LCIG) model based on Bi-directional Long Short-Term Memory (Bi-LSTM) was proposed. The inputs of the Bi-LSTM were data fragments of several influencing factors including the relative velocity and the distance between the relative vehicles, the type of the preceding vehicles, and the average velocity of the adjacent traffic flows, that over a certain period of time, which was determined via examining subjects’ visual behaviors of the left view mirror or the right view mirror. By combining the…
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N&V Component Structural Integration and Mounted Component Durability Implications

General Motors LLC-Mark Stebbins, Joseph Schudt
  • Technical Paper
  • 2020-01-1396
To be published on 2020-04-14 by SAE International in United States
Exterior component integration presents competing performance challenges for balanced exterior styling, safety, ‘structural feel’ [1] and durability. Industry standard practices utilize noise and vibration mode maps and source-path-receiver [2] considerations for component mode frequency placement. This modal frequency placement has an influence on ‘structural feel’ and durability performance. Challenges have increased with additional styling content, geometric overhang from attachment points, component size and mass, and sensor modules. Base excitation at component attachment interfaces are increase due to relative positioning of the suspension and propulsion vehicle source inputs. These components might include headlamps, side mirrors, end gates, bumpers and fascia assemblies. Here, we establish basic expectations for the behavior of these systems, and ultimately consolidate existing rationales that are applied to these systems. We consider a simple two degree-of-freedom system subject to a base excitation consisting of masses attached via springs and dampers. Component mode decoupling, vibration amplification and basic design guidance relationships are suggested.
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Virtual Verification of Light Reflection for Cluster and Side Mirror in Real Time Scenario

VE Commercial Vehicles Ltd.-Manas Bhatnagar, Jyotiranjan Biswal, Saurabh Sharma
  • Technical Paper
  • 2020-01-0568
To be published on 2020-04-14 by SAE International in United States
In the very automobile world trends are changing at a very fast pace, due to continuous expectation changes by user and new regulatory requirements demand from government authorities with a very stringent timeline.In the current scenario, manufacturer has to wait for mock up for concept selection and physical proto build to conclude open points of design verification. This complete process takes more than a year to enhance the design maturity for further builds.In VECV we have created Cluster design standard to meet different level of cluster illumination & reflection at virtual level. We are defining the cluster light illumination based on our rigorous study on cluster reflection impact on side glass, windscreen and mirror. Accordingly we have packaged our mirror to minimize the impact of cluster reflection on mirror visibility.With the help of virtual verification of cluster and Side mirror inter co-relation of packaging, we significantly reduced the time loss and save huge cost required for developing proto build. Different options of mirror and cluster can be verified in quick session. With the help of…
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Advances in Experimental Vehicle Soiling Tests

FKFS-Timo Kuthada, Jochen Wiedemann, Andreas Wagner
IVK - University of Stuttgart-Felix Schilling
  • Technical Paper
  • 2020-01-0681
To be published on 2020-04-14 by SAE International in United States
The field of vision of the driver during wet road conditions, as well as the visibility of the vehicle, is essential for safety at all times. Additionally, the safe use of the increasing number of sensors integrated in modern cars for autonomous driving and intelligent driver assistant systems has to be ensured even under challenging weather conditions. Thus, soiling investigations are of major importance in the development process of new cars. To fulfil these requirements during the development process of new cars, experimental and numerical investigations of vehicle soiling are performed. This paper examines the surface contamination of self and foreign soiling considering side, rear, side window as well as side mirror, tested in the wind tunnel. For this type of tests, the fluorescence media method is state-of-the-art and widely used for visualizing critical areas. In the last years the importance of parameters like the contact angle have been identified when designing the experimental setup. In addition, new visualisation techniques have been introduced. Based on these developments the complete process using the fluorescence method was…
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Aerodynamic Optimization of Vehicle Configuration Based on Adjoint Method

ANSYS Inc.-Tushar Jadhav
SAIC Volkswagen Automotive Co., Ltd.-Chao Ren, Hua Zhou, Haibo Wu, Qian Chen
  • Technical Paper
  • 2020-01-0915
To be published on 2020-04-14 by SAE International in United States
Due to the increasingly stringent environmental regulations all around the world confronted by exhaust emission and energy consumption, improving fuel economy has been the top priority for most automotive manufacturers. In this context, the basic process for vehicle shape development has evolved into optimizing the design to achieve better aerodynamic characteristics, especially drag reduction. Of all the optimization approaches, the gradient-based adjoint method has currently received extensive attention for its high efficiency in calculating the objective sensitivity with respect to geometry parameters, which is the first and foremost step for subsequent shape modification.In this work, the main goal is to explore the adjoint method through optimizing the vehicle shape for a lower drag based on a production SUV. Firstly, the influence of different mesh schemes was discussed on sensitivity prediction of aerodynamic drag. Secondly, according to the sensitivity distribution, several key areas, like the side mirrors, A pillars, air dam, and rear lamps, were respectively altered through mesh morphing process. Furthermore, the optimized effect was validated by steady as well as transient simulation. Steady Reynolds…
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SUPPLIER EYE

Automotive Engineering: March 2020

  • Magazine Article
  • 20AUTP03_07
Published 2020-03-01 by SAE International in United States

A decade from now, how will our rear-view mirrors percieve the current period of industry disruption? These are strategically pivotal times. Incumbent OEMs, suppliers and the dozens of newcomers challenging them face the dynamics of a constantly changing and unpredictable ecosystem.

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Friction Reduction of an All-aluminum Cylinder for Motorcycles by a Mirror Finished Bore with Dimples

Yamaha Motor Co., Ltd-Yuta Murase, Hideya Kumagai
  • Technical Paper
  • 2019-32-0530
Published 2020-01-24 by Society of Automotive Engineers of Japan in Japan
In recent years, the demand for fuel economy of small engines has been increasing for further improvement of product competitiveness. As a solution for this issue, a lot of developments on reduction of friction losses of engine components have been actively performed by engine manufacturers, especially the friction loss between the cylinder bores and pistons or piston rings is main issue to solve because these frictions highly contribute to the fuel economy for the small engines. In this study, focusing on the effect of the texture of the all-aluminum cylinder bore on friction loss, we verified the friction loss of all-aluminum cylinders having several kinds of surface textures by a floating liner method. For the evaluation, we prepared cylinders which have the texture of the following three types, 1) plateau type (having conventional cross-hatches), 2) mirror finished type (having no cross-hatches and no irregular surface characteristics), 3) dimple type (most of part is mirror finished but small dimples are given at a limited part). As a result of the evaluation, it was confirmed that FMEP…
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A mirrorless future? NHTSA seeks input on camera vision systems

Automotive Engineering: November/December 2019

Lindsay Brooke
  • Magazine Article
  • 19AUTP11_13
Published 2019-11-01 by SAE International in United States

The U.S. National Highway Traffic Safety Administration (NHTSA) in early October distributed a notice soliciting industry and public input on whether to allow “camera monitoring systems” to replace rear- and sideview exterior mirrors mandated since 1968 in U.S. auto safety standards. The agency said in a notice in the online Federal Register that it is seeking outside research and data about the potential safety impacts of replacing conventional fixed mirrors with camera-based vision systems. The action is one step in the process to inform a potential proposal to alter the mirror requirement for future production vehicles sold in the U.S.

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