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Pixelated-LEDs Car Headlight Design for Smart Driving and CO2 Reduced Emissions.

University of Versailles-Sidahmed Beddar, Jean-Baptiste Millet, Yasser Alayli
  • Technical Paper
  • 2020-37-0018
To be published on 2020-06-23 by SAE International in United States
The advent of Electroluminescent Diode (LED) technologies has been one of the major sources of energy reduction in the domestic lighting sector as well as in the automotive and aerospace fields. In vehicles, the use of LEDs allows a reduction of 110W to 40W useful for the function Dipped-beam is a gain of about 350W in energy consumption of the vehicle with a combustion engine (from 2 to 5g of CO2 per kilometer). In 2010, Adaptive Dipped Beam (ADB (also called glare-free high beam) appeared. The objective of the ADB is to adapt the beam to the presence of vehicles in both directions to improve the driver's long-range visibility without causing discomfort, distraction or glare to other road users. The ADB is a lighting function with high added value in terms of comfort and road safety. The new lighting technologies make this function more and more efficient and effective with a resolution and the number of pixels that increases Pixelated LEDs, by offering various advantages over other architectures, are gaining market shares. They are more…
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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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Investigations on Headlamp and Car Body Tolerances in Real Life

Audi AG-Michael Hamm, Christian Hinterwalder
  • Technical Paper
  • 2020-01-0635
To be published on 2020-04-14 by SAE International in United States
Good Lighting is cruicial for safe driving at night. Unfortunately many parameters are contributing to the final result of the individual tolerances of car body, dynamics and headlamp: The resulting aim. The paper will collect and analyse tolerance contributors from body parameters like load, tire pressure, suspension as well as aging parameters of chassis and plastic parts.
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Influence of Background Spectral Distribution on Perceptions of Discomfort Glare

Rensselaer Polytechnic Institute-Rohan M. Nagare, John D. Bullough
  • Technical Paper
  • 2020-01-0637
To be published on 2020-04-14 by SAE International in United States
The advent of light-emitting diode (LED) technology for automotive lighting allows flexibility of the spectral distribution of forward headlighting systems, while meeting current requirements for “white” illumination. As vehicle headlights have become whiter (with more short-wavelength light output) over the past several decades, their potential impacts on visual discomfort for oncoming and preceding drivers have been hotly debated. It is known that a greater proportion of short-wavelength energy increases discomfort glare, and that increasing the background light level (e.g., through roadway lighting) will decrease perceptions of discomfort. More recently it has been demonstrated that the visual system exhibits enhanced short-wavelength sensitivity for perceptions of scene brightness. As a result, roads illuminated by light sources with higher correlated color temperatures (CCTs) will be judged as appearing to be brighter than those illuminated to the same light level by sources with lower CCTs. The present laboratory study was conducted to identify whether the increased scene brightness of a road illuminated with greater short-wavelength light helps to mitigate discomfort glare more than the same scene illuminated to the…
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Influence of Intensity, Duration and Spectral Characteristics on Glare Recovery for Peripheral Visibility

Rensselaer Polytechnic Institute-Nicholas P. Skinner, John D. Bullough
  • Technical Paper
  • 2020-01-0632
To be published on 2020-04-14 by SAE International in United States
Vehicle forward lighting can use a multiplicity of light sources each varying in their spectral characteristics. Present standards for low beam headlight performance also allow variability in the peak intensities that drivers can be exposed to, as well as the durations of those exposures. Previous research has led to mixed results regarding whether the spectral distribution of a headlight source influences the length of time the visual system needs to recover the ability to see objects that might present hazards along the roadway. One recent study showed that the integrated light dose (intensity × duration) but not the spectral distribution impacted recovery times for targets presented in a constant, known location, where they would be viewed with the fovea. An experiment was carried out to assess whether the spectral distribution of a glare source might differentially impact one's ability to see a target using peripheral vision when the location of the target is not known. The findings indicate that a light source with greater short-wavelength light output resulted in longer recovery times when matched for…
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Does the Interaction between Vehicle Headlamps and Roadway Lighting Affect Visibility? A Study of Pedestrian and Object Contrast

Virginia Tech-Maury Nussbaum
Virginia Tech Transportation Institute-Rajaram Bhagavathula, Ron Gibbons
  • Technical Paper
  • 2020-01-0569
To be published on 2020-04-14 by SAE International in United States
Vehicle headlamps and roadway lighting are the major sources of illumination at night. These sources affect contrast - defined as the luminance difference of an object from its background - which drives visibility at night. However, the combined effect of vehicle headlamps and intersection lighting on object contrast has not been reported previously. In this study, the interactive effects of vehicle headlamps and overhead lighting on object contrast were explored based on earlier work that examined drivers’ visibility under three intersection lighting designs (illuminated approach, illuminated box, and illuminated approach + box). The goals of this study were to: 1) quantify object luminance and contrast as a function of a vehicle’s headlamps and its distance to an intersection using the three lighting designs; and, 2) to assess whether contrast influences visual performance and perceived visibility in a highly dynamic intersection environment. Both luminance and contrast of roadway visibility targets and a pedestrian were measured with a calibrated photometer at a realistic intersection. Both target and pedestrian contrast and luminance were substantially affected by the intersection…
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Unsteady Flow Analysis Method for Automobile LED Headlamp based on Massively Parallel CFD considering the External Environment

Hiroshima University-Takuji Nakashima
Kobe University-ChungGang Li, Makoto Tsubokura
  • Technical Paper
  • 2020-01-0636
To be published on 2020-04-14 by SAE International in United States
The aim of this study is to understand the mechanism of dew condensation and try to prevent it on automobile headlamp. In this case, it is necessary to accurately reproduce the complicated shape of the headlamp as the computational model. In addition, the simulation framework for predicting the turbulent flow field accompanied by the high heat source and the wall heat transfer with high accuracy in the vehicle running environment is required. Moreover, using CFD to understand the mechanism of the flow field inside the light emitting diode (LED) headlamp with a rotating fan to cool the light sources, is a challenging task because of the complicated internal structures and significant heat transfer. In this paper, we report that we tried constructing the simulation method of compressible turbulence based on hierarchical Cartesian grid using the HPC (High Performance Computing) environment. At first, we clarified the ventilation phenomenon through the vent holes in the uniform flow, and succeeded in obtaining the knowledge of ventilation control by changing the position and number of the vent holes. The…
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new

Full Adaptive Forward Lighting Systems

Road Illumination Devices Standards Committee
  • Ground Vehicle Standard
  • J2838_202003
  • Current
Published 2020-03-12 by SAE International in United States
This SAE standard provides test procedures, performance requirements, design guidelines and installation guidelines for full adaptive forward lighting systems (AFS).
This content contains downloadable datasets
Annotation ability available
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new

Sensor Heat Relief

Autonomous Vehicle Engineering: March 2020

Bradley Berman
  • Magazine Article
  • 20AVEP03_07
Published 2020-03-01 by SAE International in United States

Canatu's carbon nanobots keep critical sensor surfaces -and LED headlamps - clean in sub-freezing weather.

Sensor surfaces that are exposed to weather need to be kept clean so that ADAS and autonomous driving systems can function safely. Ice build-up in cold conditions is of particular concern, but Canatu thinks it has a solution.

Annotation ability available
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Motorcycle Headlamps

Motorcycle Lighting Committee
  • Ground Vehicle Standard
  • J584_202002
  • Current
Published 2020-02-17 by SAE International in United States
This SAE Standard provides test procedures, performance requirements, design guidelines, and installation guidelines for motorcycle headlamps.
This content contains downloadable datasets
Annotation ability available