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Technical Paper

Wind-Averaged Drag Determination for Heavy-Duty Vehicles Using On-Road Constant-Speed Torque Tests

2016-09-27
2016-01-8153
To investigate the feasibility of various test procedures to determine aerodynamic performance for the Phase 2 Greenhouse Gas (GHG) Regulations for Heavy-Duty Vehicles in the United States, the US Environmental Protection Agency commissioned, through Southwest Research Institute, constant-speed torque tests of several heavy-duty tractors matched to a conventional 53-foot dry-van trailer. Torque was measured at the transmission output shaft and, for most tests, also on each of the drive wheels. Air speed was measured onboard the vehicle, and wind conditions were measured using a weather station placed along the road side. Tests were performed on a rural road in Texas. Measuring wind-averaged drag from on-road tests has historically been a challenge. By collecting data in various wind conditions at multiple speeds over multiple days, a regression-based method was developed to estimate wind-averaged drag with a low precision error for multiple tractor-trailer combinations.
Journal Article

Wind Tunnel and Track Tests of Class 8 Tractors Pulling Single and Tandem Trailers Fitted with Side Skirts and Boat-tails

2012-04-16
2012-01-0104
A 1:10-scale wind tunnel development program was undertaken by the National Research Council of Canada and Airshield Inc. in 1994 to develop trailer side skirts that would reduce the aerodynamic drag of single and tandem trailers. Additionally, a second wind tunnel program was performed by the NRC to evaluate the fuel-saving performance of boat-tail panels when used in conjunction with the skirt-equipped single and tandem trailers. Side skirts on tandem, 8.2-m-long trailers (all model dimensions converted to full scale) were found to reduce the wind-averaged drag coefficient at 105 km/h (65 mi/h) by 0.0758. The front pair of skirts alone produced 75% of the total drag reduction from both sets of skirts and the rear pair alone produced 40% of that from both pairs. The sum of the drag reductions from front and rear skirts separately was 115% of that when both sets were fitted, suggesting an interaction between both.
Technical Paper

Wind Tunnel Test of Cab Extender Incidence on Heavy Truck Aerodynamics

2005-11-01
2005-01-3527
A wind tunnel experiment has been conducted to determine the changes in drag and side force due to the presence and position of cab extenders on a model of a commercial tractor-trailer truck. The geometric variables investigated are the cab extenders angle of incidence, the tractor-trailer spacing and the yaw angle of the vehicle. Three cab extender angles were tested-0°, 15° (out) and -15° (in) with respect to the side of the tractor. The cab and trailer models have the same width and height. The minimum drag coefficient was found for the tractor and trailer combination when the cab extenders were set to 0° angle of incidence with respect to the headwind. This result holds for all yaw angles with moderate gap spacing between the tractor and trailer. This study suggests that commercial tractor-trailer trucks can benefit from adjustable cab extender settings; 0° when using a trailer and -15° when no trailer is used.
Technical Paper

Wind Tunnel Evaluation of Potential Aerodynamic Drag Reductions from Trailer Aerodynamic Component Combinations

2015-09-29
2015-01-2884
The use of devices to reduce aerodynamic drag on large trailers and save fuel in long-haul, over-the-road freight operations has spurred innovation and prompted some trucking fleets to use them in combinations to achieve even greater gains in fuel-efficiency. This paper examines aerodynamic performance and potential drag reduction benefits of using trailer aerodynamic components in combinations based upon wind tunnel test data. Representations of SmartWay-verified trailer aerodynamic components were tested on a one-eighth scale model of a class 8 sleeper tractor and a fifty three foot, van trailer model. The open-jet wind tunnel employed a rolling floor to reduce floor boundary layer interference. The drag impacts of aerodynamic packages are evaluated for both van and refrigerated trailers. Additionally, the interactions between individual aerodynamic devices is investigated.
Technical Paper

Wind Tunnel Concepts for Testing Heavy Trucks

2016-09-27
2016-01-8144
The trucking industry is being encouraged by environmental and cost factors to improve fuel efficiency. One factor that affects fuel efficiency is the aerodynamic design of the vehicles; that is, the vehicles with lower aerodynamic drag will get better mileage, reducing carbon emissions and reducing costs through lower fuel usage. A significant tool towards developing vehicles with lower drag is the wind tunnel. The automobile industry has made great improvements in fuel efficiency by using wind tunnels to determine the best designs to achieve lower drag. Those wind tunnels are not optimum for testing the larger, longer heavy trucks since the wind tunnels are smaller than needed. The estimated costs for a heavy truck wind tunnel based on automotive wind tunnel technology are quite high. A potential nozzle concept to reduce wind tunnel cost and several other new possible approaches to lower wind tunnel costs are presented.
SAE MOBILUS Subscription

Wiley SAE MOBILUS® eBook Package

2018-03-23
Committed to being the primary source for aerospace and ground vehicle engineering resources, SAE International has added the full compilation of our Wiley eBook collections to the SAE MOBILUS® technical resource platform. Purchasable as an annual subscription and containing the titles from the Wiley Aerospace Collection, the Wiley Automotive Collection, the Wiley Computer Systems Collection, and the Wiley Cyber Security Collection.
Technical Paper

Weight Optimization of Off Highway Equipment Assembly

2011-10-06
2011-28-0096
Weight reduction in construction equipment is sought to achieve energy conservation and also to comply with the vehicle safety and compliance regulations, managing the weight distribution across the rear and the front end of the equipment to achieve the optimum balancing. Of late the thrust on product weight has increased along with reduced time to market, leading to increased usage of structural optimization methods. This has been further supported by the availability of high performance computing at relatively low cost. VOC and CTQ tools provided the motivation and initial screening of the design variables. The structural optimization software provides an integrated platform for analysis as well as optimization of components. In this work, an optimization tool has been used for size and shape optimization of a construction equipment assembly and a commercial FEA package was used for verification and validation of the results.
Technical Paper

Weed Recognition Using Machine Vision and Color Texture Analysis

1996-08-01
961759
The environmental impact from herbicide utilization has been well documented in recent years. The reduction in weed control with out a viable alternative will likely result in decreased per acre production and thus higher unit production cost. The potential for selective herbicide application to reduce herbicide usage and yet maintain adequate weed control has generated significant interest in different forms of remote sensing of agricultural crops. This research evaluated the color co-occurrence texture analysis technique to determine its potential for utilization in crop groundcover identification. A program termed GCVIS (Ground Cover VISion) was developed to control an ATT TARGA 24 frame grabber; and generate HSI color features from the RGB format pixel data, HSI CCM matrices and the co-occurrence texture feature data.
Technical Paper

Vehicle Performance of Mini Tracked UGVs for Different Terrains Using Off-Road Vehicle Engineering Techniques

2015-01-14
2015-26-0144
This paper discusses the off-road performance prediction of military application mini UGVs using terramechanics work deals with the development of performance simulation model for mini UGV in the Matlab/Simulink Software. Transient forward vehicle propulsion model and soil terrain interaction model have been built in the Simulink® software. It is a semi-empirical mobility model which predicts mini UGV performance on given terrain. The interaction between vehicle and the terrain causes resistances to vehicle propulsion. The model calculates these resistances, compares them to both the power limitations of the vehicle and the tractive limitations of the soil/terrain, to determine if the vehicle is immobilized. If not, then the vehicle speed is calculated based on available drawbar pull. The terrain is defined in terms of the soil parameters measured by the Bevameter. Semi-empirical equations suggested by Bekker have been used to model the soil terrain interaction.
Standard

Vehicle Identification Numbers--Snowmobiles

1988-04-01
HISTORICAL
J64_198804
This SAE Standard is intended to provide uniform requirements for the visibility and durability of vehicle identification numbers on snowmobiles.
Standard

Vehicle Identification Numbers--Snowmobiles

2007-02-21
CURRENT
J64_200702
This SAE Standard is intended to provide uniform requirements for the visibility and durability of vehicle identification numbers on snowmobiles.
Standard

Vehicle Identification Numbers--Snowmobiles

1973-03-01
HISTORICAL
J64_197303
This SAE Standard is intended to provide uniform requirements for the visibility and durability of vehicle identification numbers on snowmobiles.
Technical Paper

Vehicle Electrical Interconnection Systems-in Search of Reliability?

1989-11-01
892511
The design complexity of today's vehicles places tougher demands on the electrical interconnection system, particularly within the engine compartment. This paper outlines three areas of product development specifically aimed at improving the performance of such systems. These are: ENVIRONMENTAL SEALING AND PROTECTION of multiple wire splices, wire bundles, and connectors. VEHICLE WIRING, with particular regard to high temperature resistance on critical components such as ABS systems. ELECTROMAGNETIC INTERFERENCE (EMI) PROTECTION via the use of shielded cables, and simple and reliable shield termination/splicing techniques. Together, these new materials and products combine to provide tougher, smaller, higher temperature resistance and environmentally sealed electrical interconnection systems.
Technical Paper

Vehicle Duty Cycle Characteristics for Hybrid Potential Evaluation

2012-09-24
2012-01-2023
A range of cycle characteristics have been used to estimate the hybrid potential for vehicle duty cycles including characteristic acceleration, aerodynamic velocity, kinetic intensity, stop time, etc. These parameters give an indication of overall hybrid potential benefits, but do not contain information on the distribution of the available braking energy and the hybrid system power required to capture the braking energy. In this paper, the authors propose two new cycle characteristics to help evaluate overall hybrid potential of vehicle cycles: P50 and P90, which are non-dimensional power limits at 50% and 90% of available braking energy. These characteristics are independent of vehicle type, and help illustrate the potential hybridization benefit of different drive cycles. First, the distribution of available braking energy as a function of brake power for different vehicle cycles and vehicle classes is analyzed.
Journal Article

Vehicle Demonstration of 2 Stroke Engine Brake in a Heavy Duty Truck

2016-09-27
2016-01-8061
Heavy duty valvetrains have evolved over the last 20 years with the integration of engine braking into the valvetrain. Jacobs Vehicle Systems have developed the High Power Density (HPD) engine brake that increases retarding powe, especially at low engine speed. The system works by converting the engine from a 4 stroke during positive power into a 2 stroke for retarding power. This more than doubles the retarding power at cruise engine speeds reducing the need to downshift in order to control the vehicle, compensates for reduction in natural vehicle retarding due to aerodynamic and friction enhancements, and enables the same vehicle retarding power with a smaller displacement engine as engine downsizing becomes prevalent. This paper describes lessons learnt during a recent vehicle demonstration project undertaken by Jacobs including performance, durability, integration with the engine powertrain, controls development, calibration, management of air system and transient operation.
Collection

Vehicle Aerodynamics, 2018

2018-04-03
Vehicle aerodynamic development, drag reduction and fuel economy, handling and stability, cooling flows, surface soiling and water management, vehicle internal environment, tyre aerodynamics and modelling, aeroacoustics, structural response to aerodynamic loading, simulating the on-road environment, onset flow turbulence, unsteady aerodynamics, fundamental flow structures, new test methods and facilities, new applications of computational fluid dynamics simulation, competition vehicle aerodynamics.
Collection

Vehicle Aerodynamics, 2017

2017-03-28
Vehicle aerodynamic development, drag reduction and fuel economy, handling and stability, cooling flows, surface soiling and water management, vehicle internal environment, tyre aerodynamics and modelling, aeroacoustics, structural response to aerodynamic loading, simulating the on-road environment, onset flow turbulence, unsteady aerodynamics, fundamental flow structures, new test methods and facilities, new applications of computational fluid dynamics simulation, competition vehicle aerodynamics.
Technical Paper

Validation Study for the Introduction of an Aerodynamic Development Process of Heavy Trucks

2014-09-30
2014-01-2444
A challenge for the aerodynamic optimization of trucks is the limited availability of wind tunnels for testing full scale trucks. FAW wants to introduce a development process which is mainly based on CFD simulation in combination with some limited amount of wind tunnel testing. While maturity of CFD simulation for truck aerodynamics has been demonstrated in recent years, a complete validation is still required before committing to a particular process. A 70% scale model is built for testing in the Shanghai Automotive Wind Tunnel Center (SAWTC). Drag and surface pressures are measured for providing a good basis for comparison to the simulation results. The simulations are performed for the truck in the open road driving condition as well as in an initial digital model of the aerodynamic wind tunnel of SAWTC. A full size truck is also simulated in the open road driving condition to understand the scaling effect.
Technical Paper

Validation Studies for an Advanced Aerodynamic Development Process of Cab-Over Type Heavy Trucks

2017-10-25
2017-01-7009
The implementation of an advanced process for the aerodynamic development of cab-over type heavy trucks at China FAW Group Corporation (FAW) requires a rigorous validation of the tools employed in this process. The final objective of the aerodynamic optimization of a heavy truck is the reduction of the fuel consumption. The aerodynamic drag of a heavy truck contributes up to 50% of the overall resistance and thus fuel consumption. An accurate prediction of the aerodynamic drag under real world driving conditions is therefore very important. Tools used for the aerodynamic development of heavy trucks include Computational Fluid Dynamics (CFD), wind tunnels and track and road testing methods. CFD and wind tunnels are of particular importance in the early phase development.
Technical Paper

Validating Heavy-Duty Vehicle Models Using a Platooning Scenario

2019-04-02
2019-01-1248
Connectivity and automation provide the potential to use information about the environment and future driving to minimize energy consumption. Aerodynamic drag can also be reduced by close-gap platooning using information from vehicle-to-vehicle communications. In order to achieve these goals, the designers of control strategies need to simulate a wide range of driving situations in which vehicles interact with other vehicles and the infrastructure in a closed-loop fashion. RoadRunner is a new model-based system engineering platform based on Autonomie software, which can collectively provide the necessary tools to predict energy consumption for various driving decisions and scenarios such as car-following, free-flow, or eco-approach driving, and thereby can help in developing control algorithms.
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