Fast charging is attractive to battery electric vehicle (BEV) drivers for its ability to enable long-distance travel and to quickly recharge depleted batteries on short notice. However, such aggressive charging and the sustained vehicle operation that results could lead to excessive battery temperatures and degradation. Properly assessing the consequences of fast charging requires accounting for disparate cycling, heating, and aging of individual cells in large BEV packs when subjected to realistic travel patterns, usage of fast chargers, and climates over long durations (i.e., years). The U.S. Department of Energy's Vehicle Technologies Office has supported the National Renewable Energy Laboratory's development of BLAST-V-the Battery Lifetime Analysis and Simulation Tool for Vehicles-to create a tool capable of accounting for all of these factors. We present on the findings of applying this tool to realistic fast charge scenarios.
Intermodal transport creates many difficulties insofar as the handling of liability claims is concerned. Different conventions have been established in an attempt to solve these problems; and a brief review of these is presented. Also examined is an attempt by various countries to establish an international convention which would apply whenever goods are carried between two or more countries by two or modes of transportation. Although many difficulties have arisen with this convention, it is hoped that they may be ironed out and that the resolution be adopted.
This technical paper and presentation addresses the need for more refined, pervasive and highly engaged technical leadership in the system safety discipline. Systems engineering disciplines have been led to believe that by following a single industry standard, generic plans, inflexible processes, proven methods and techniques a system with low safety risk will evolve with little rework. The truth is there is no prescriptive one size fits all approach, or a convention that will anticipate and cover all needs. In several domain areas, especially modern military and commercial airborne systems, diverse technology and functionality have been evolving with such high complexity and criticality that collective processes will not work unless seasoned leaders allow creativity and innovation to be part of the safety culture. Leaders must have intuitive engineering and operations judgment to determine how to best allocate effective resources to meet system safety goals and objectives.
Established in 1971, this award provides for an annual lecture dealing with a broad phase of civil air transportation considered of current interest and major importance. The objective is to advance air transport engineering and to recognize those who make personal contributions to the field. The award perpetuates the memory of William Littlewood, the only person ever to be president of both SAE (1954) and the American Institute of Aeronautics and Astronautics. He was renowned for his contributions to the design of, and operational requirements for, civil transport aircraft. The award consists of a framed certificate and a $8000 honorarium and is presented each year at a national meeting of one of the sponsoring societies.
This grant provides funding to a Formula SAE® team to assist with the development of their project. Applicants must be registered for the competition at the time of application. Teams wishing to use these funds for anything other than vehicle design will be eliminated. Special attention will be given to those teams who were unable to secure major sponsors for their team. This grant honors William R. "Bill" Adam's contribution to FSAE and his lifelong dedication to mentoring young engineers. A 35-year member of SAE and long time supporter of FSAE, Bill was an engineer in the automotive industry for more than 40 years working on vehicle development, testing and correlation. He was a co-patent developer of integrated Manifold-Muffler-Catalyst design and had seven years experience with exhaust development and exhaust pass-by noise levels. Established in 2004, this grant is administered by the SAE Foundation, and applications are reviewed by Mrs. Pat Adam and Mrs.
Increasingly, vehicle engineers of all backgrounds are being taxed with restrictions on time, equipment and facilities due to competitive demands for cost and lead-time reductions. This has precipitated an industry-wide interest in processes which address these restrictions and allow engineers to “do more with less.” Vehicle sound system development is just one example of a standard, necessary phase of premium vehicle design subject to continuous cutbacks. This complex, time-consuming effort spans a variety of disciplines such as transducer design, psychoacoustics and digital filters. However, the most significant contribution to the overall performance exists in the tuning of such system parameters as equalization, crossovers, gain staging, time-alignment, and other vehicle-specific audio parameters.
There is a limited amount of data in literature discussing dynamic instability of tractor trailers due to wind speed and wind gusts on slippery surfaces. This paper outlines an analytical approach to assess tractor trailer performance due to these factors. The paper considers short-period wind gusts as well as uplift effect of the wind, frictional properties of the roadway, vehicle speed, jackknife effects, inertial (both translational and rotational) properties of tractor trailer combinations. Correlation between parameters related to semi dynamic instabilities are offered in a graphical format.
A study was made to determine the effectiveness of low power wind energy harvesting for mobile applications. Experimental and simulated data has shown that harvesting of alternative energy resources is viable for potential mobile applications. This conducted study incorporated a mobile configuration consisting of a wind-photovoltaic hybrid in concert with a vehicle generator. The study has demonstrated an improvement in overall efficiency of the power generation system.
This paper is concerned with the development of statistical models for the gust field in the lowest 300 ft of the atmosphere. It presents some of the highlights of the underlying physics principles, what is known about gusts, and how gusts affect aircraft. The difficulties of developing gust models are accounted for by the lack of data in particular areas and thus direct attention to the work required to provide the needed information.
The principle cause of objectionable wind noise in the modern automobile is small air leaks in certain critical areas. The aerodynamic shape is insignificant in overall wind noise. The critical areas in order of importance are: 1. Vent window and door to “A” post sealing from the roof rail to about a foot below the beltline. 2. “C” post area at beltline. 3. Upper rear of front door area. 4. All other areas from roof rail to a foot below the beltline. Conclusions reached after extensive testing show that wind noise can be eliminated by good sealing about the doors and windows.
In order to understand the flow and wind noise characteristics generated by the outside rearview (OSRV) mirror, a series of wind noise measurements for two production mirrors was conducted at the GM Aerodynamics Lab (GMAL) wind tunnel. These measurements included the time-averaged static pressures, surface noise sources, and far field propagation noise. The data obtained in this investigation will be used for future CFD numerical validations. The two mirrors chosen for the test are the GMT360 (a truck mirror) and the GMX320 (a sedan mirror). The test mirror was mounted on an elevated table which was specially designed for the current project to avoid any significant flow boundary layer buildup on the wind tunnel floor. The test conditions reported in this paper include four inlet speeds of 30, 50, 70 and 90 mph at 0 yaw angle. To record the wind noise sources, nine surface flush-mount microphones were used.
A vehicle's underbody has various wind noise sources due to the complex flow structure. Acoustic holography using NAH (Near-field Acoustic Holography) is adopted to identify the sources, and to analyze the characteristics of them such as positions, strengths, and contributions to interior sound. Reduction procedure of wind noise from a vehicle's underbody will be investigated.
Wind noise is the sound made as air rushes over a moving vehicle. As other vehicle sound sources are improved, the wind noise becomes the dominant source under certain conditions. The purpose of this paper is to examine the relationship between the properties of wind noise and the human perception of this sound.We find that a particular loudness measure (Zwicker loudness as defined in IS0532B) is the prime factor governing the customer perception of wind noise.
Recent developments in the prediction of the contribution of wind noise to the interior SPL have opened a realm of new possibilities in terms of i) how the convective and acoustic sources terms can be identified, ii) how the interaction between the source terms and the side glass can be described and finally iii) how the transfer path from the sources to the interior of the vehicle can be modelled. This paper discusses in detail these three aspects of wind noise simulation and recommends appropriate methods to deliver required results at the right time based on i) simulation and experimental data availability, ii) design stage and iii) time available to deliver these results. Several simulation methods are used to represent the physical phenomena involved such as CFD, FEM, BEM, FE/SEA Coupled and SEA.
Wind noise in automobile is becoming more and more important as customer requirements increase. On the other hand great progress has been made on engine and road noises. Thus, for many vehicles, wind noise is the major acoustic source during road and motorway driving. As for other noises, automobile manufacturers must be able for a new car project to specify, calculate and measure each step of the acoustic cascading: Source Transfers, both solid and air borne In the case of automotive wind noise, the excitation source is the dynamic pressure on the vehicle’s panels. This part of the cascading is the one influenced by the exterior design. Even if many others components (panels, seals, cabin trims) have a big influence, the exterior design is a major issue for the wind noise. The wind noise level in the cabin can sometimes change significantly with only a small modification of the exterior design.
The current ability of the Virtual Aerodynamic/ Aeroacoustic Wind Tunnel to predict interior vehicle sound pressure levels is demonstrated using an automobile model which has variable windshield angles. This prediction method uses time-averaged flow solutions from a lattice gas CFD code coupled with wave number-frequency spectra for the various flow regimes to calculate the side window vibration from which the sound pressure level spectrum at the driver's ear is determined. These predictions are compared to experimental wind tunnel data. The results demonstrate the ability of this methodology to correctly predict wind noise spectral trends as well as the overall loudness at the driver's ear. A more sophisticated simulation method employing the same lattice gas code is investigated for prediction of the time-accurate flow field necessary to compute the actual side glass pressure spectra.