Model-Based Estimation of Vehicle Aerodynamic Drag and Rolling Resistance

2015 ◽  
Vol 8 (2) ◽  
pp. 433-439 ◽  
Author(s):  
Darui Zhang ◽  
Andrej Ivanco ◽  
Zoran Filipi
Keyword(s):  
Aerodynamic Drag ◽  
Rolling Resistance ◽  
Model Based

scholarly journals Aerodynamic Drag and Rolling Resistance of Three-Wheelers

2009 ◽  
Vol 42 (4) ◽  
pp. 21
Author(s):  
J. A. K. S. Jayasinghe ◽  
B. S. Samarasiri ◽  
G. M. A. I. Rajakaruna
Keyword(s):  
Aerodynamic Drag ◽  
Rolling Resistance

A New Cavitation Model Based on Evaporation and Condensation Theory

2009 ◽  
Author(s):  
Gang Chen ◽  
Shuhong Liu ◽  
Guangjun Cao ◽  
Yulin Wu ◽  
Suhong Fu ◽  
...  
Keyword(s):  
Surface Tension ◽  
Aerodynamic Drag ◽  
Water Pressure ◽  
Bubble Diameter ◽  
Simulation Models ◽  
Cavitation Model ◽  
Local Pressure ◽  
Two Phase ◽  
Evaporation And Condensation ◽  
Model Based

Cavitation is a phenomenon which occurs where the local pressure falls off under the vapor pressure. Over the past few years, numerical simulation models for cavitation have been developed significantly in order to investigate the mechanism of cavitation. In the paper, A local homogeneous cavitation model based on the theory of evaporation and condensation has been deduced, which is used to describe the phase change between water and vapor. The RNG k–ε turbulence model is used to simulate the turbulent flow and the finite volume method is employed to discrete the governing equations. The effects of surface tension of water, pressure fluctuations and non-condensable gases are included in the mass transfer cavitation model. Also in order to neglect the effects of the quantities such as the bubble number and bubble diameter, which is difficult to measure, the relations between the aerodynamic drag and surface tension forces is used to describe the bubble diameter. In order to evaluate the new cavitation model, the two phase cavitation flows around a NACA0015 hydrofoil at different attack angle and different cavitation number are simulated by the new cavitation model, and compared with references, which showed good agreement with the experiments.

A Study on the Aerodynamic Drag of a Non-Pneumatic Tire

2012 ◽  
Author(s):  
Hyeonu Heo ◽  
Jaehyung Ju ◽  
Doo-Man Kim ◽  
Sangwa Rhie
Keyword(s):  
Drag Force ◽  
Aerodynamic Drag ◽  
Fuel Efficiency ◽  
Rolling Resistance ◽  
Navier Stokes ◽  
Viscoelastic Materials ◽  
Complex Flow ◽  
Pneumatic Tire ◽  
Rans Method ◽  
Pneumatic Tires

An understanding of the flow around a tire in contact with the ground is important for when designing a fuel efficient tire as aerodynamic drag accounts for about one third of an entire vehicle’s rolling loss [1]. Recently, non-pneumatic tires (NPTs) have drawn attention mainly due to their low rolling resistance associated with the use of low viscoelastic materials in their construction. However, an NPT’s fuel efficiency should be re-evaluated in terms of aerodynamic drag: discrete flexible spokes in an NPT may cause more aerodynamic drag, resulting in greater rolling resistance. In this study, the aerodynamic flow around an NPT in contact with the ground is investigated for i) stationary and ii) rotating cases using the Reynolds-Averaged Navier-Stokes (RANS) method. The NPT has a more complex flow and a higher drag force than does the pneumatic counterpart.

scholarly journals Nonlinear Controllers for a Light-Weighted All-Electric Vehicle Using Chebyshev Neural Network

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Vikas Sharma ◽  
Shubhi Purwar
Keyword(s):  
Neural Network ◽  
Electric Vehicle ◽  
Aerodynamic Drag ◽  
Rolling Resistance ◽  
Adaptive Controller ◽  
Dc Motor ◽  
Resistance Coefficient ◽  
Chebyshev Neural Network ◽  
Nonlinear Controllers ◽  
Aerodynamic Drag Coefficient

Two nonlinear controllers are proposed for a light-weighted all-electric vehicle: Chebyshev neural network based backstepping controller and Chebyshev neural network based optimal adaptive controller. The electric vehicle (EV) is driven by DC motor. Both the controllers use Chebyshev neural network (CNN) to estimate the unknown nonlinearities. The unknown nonlinearities arise as it is not possible to precisely model the dynamics of an EV. Mass of passengers, resistance in the armature winding of the DC motor, aerodynamic drag coefficient and rolling resistance coefficient are assumed to be varying with time. The learning algorithms are derived from Lyapunov stability analysis, so that system-tracking stability and error convergence can be assured in the closed-loop system. The control algorithms for the EV system are developed and a driving cycle test is performed to test the control performance. The effectiveness of the proposed controllers is shown through simulation results.

Method to Reduce Drag Coefficient for Fuel Efficiency in Semi-Truck Trailer and Trailer Stability

2018 ◽  
Author(s):  
Anu R. Nair ◽  
Fred Barez ◽  
Ernie Thurlow ◽  
Metin Ozen
Keyword(s):  
Drag Coefficient ◽  
Fuel Consumption ◽  
Aerodynamic Drag ◽  
Fuel Efficiency ◽  
Rolling Resistance ◽  
Ansys Fluent ◽  
Improve Fuel Efficiency ◽  
Area Of Interest ◽  
Streamlined Body ◽  
External Forces

Heavy commercial vehicles due to their un-streamlined body shapes are aerodynamically inefficient due to higher fuel consumption as compared to passenger vehicles. The rising demand and use of fossil fuel escalate the amount of carbon dioxide emitted to the environment, thus more efficient tractor-trailer design becomes necessary to be developed. Fuel consumption can be reduced by either improving the driveline losses or by reducing the external forces acting on the truck. These external forces include rolling resistance and aerodynamic drag. When driving at most of the fuel is used to overcome the drag force, thus aerodynamic drag proves an area of interest to study to develop an efficient tractor-trailer design. Tractor-trailers are equipped with standard add-on components such as roof defectors, boat tails and side skirts. Modification of these components helps reduce drag coefficient and improve fuel efficiency. The objective of this study is to determine the most effective geometry of trailer add-on devices in semi-truck trailer design to reduce the drag coefficient to improve fuel efficiency and vehicle stability. The methodology consisted of CFD analysis on Mercedes Benz Actros using ANSYS FLUENT. The simulation was performed on the tractor-trailer at a speed of 30m/s. The analysis was performed with various types of add-on devices such as side skirts, boat tail and vortex generators. From the simulation results, it was observed that addition of tractor-trailer add-on devices proved beneficial over modifying trailer geometry. Combination of add-on devices in the trailer underbody, rear and front sections was more beneficial in reducing drag coefficient as compared to their individual application. Improving fuel efficiency by 17.74%. Stability of the tractor-trailer is improved due to the add-on devices creating a streamlined body and reducing the low-pressure region at the rear end of the trailer.

Model Based Study of Stability Limits for Three Wheeled Vehicles Using ADAMS/Car

2011 ◽  
Author(s):  
Sughosh Rao ◽  
Anmol Sidhu ◽  
Michael Johnson ◽  
Brooks Marquette ◽  
Gary Heydinger ◽  
...  
Keyword(s):  
Fuel Efficiency ◽  
Rolling Resistance ◽  
Front Wheel ◽  
Motor Vehicles ◽  
Vehicle Design ◽  
Stable Operation ◽  
Efficient Design ◽  
Fuel Prices ◽  
Model Based ◽  
Wheeled Vehicle

Three-wheeled motor vehicles have been around for close to a half a century now, but they have largely remained in the realm of recreational or concept vehicles. Due to increasing fuel prices and an emphasis on fuel efficient design, the automotive industry is exploring the three-wheeled option now more than ever as a mainstream daily-use vehicle. The trend is evident from the Automotive X-Prize which featured six teams with three-wheeled vehicle designs to meet the fuel efficiency target [1]. A three-wheeled vehicle design offers vast potential for improvement in overall fuel efficiency over their four wheeled counterparts, as it lends itself to a tear-drop shape which is highly aerodynamic and is also likely to be lighter and have lower rolling resistance. These factors have considerable impact on improving fuel efficiency, but such a design also presents challenges in terms of vehicle stability and can be susceptible to roll-over or spin out in certain scenarios. The primary factor that determines the stability of a three-wheeled vehicle is its center of gravity (CG). This paper uses a model-based approach to explore the CG position limits for stable operation of a front wheel drive three wheel vehicle and aims to give an empirical basis for deciding CG position limits for future three wheel vehicle design. ADAMS/Car is used to model the vehicle and the model is validated using test data from a commercially available three-wheeled vehicle. The performance of the model is then studied for various CG positions and the limits of safe operation are established for this particular model.

Development of a Duty Cycle for the Design and Optimization of Advanced, Heavy-Duty Port Drayage Trucks

2017 ◽  
Vol 2609 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Pascal Amar ◽  
Parthav Desai ◽  
Aravind Kailas ◽  
Jean-Baptiste Gallo
Keyword(s):  
Real World ◽  
Duty Cycle ◽  
Greenhouse Gas Emission ◽  
Aerodynamic Drag ◽  
Electrical Power ◽  
Rolling Resistance ◽  
Conventional Vehicle ◽  
Design And Optimization ◽  
Vehicle Simulation ◽  
Drayage Trucks

Hybrid electric and electric trucks are potential technology solutions for reducing emissions at ports. However, developing an advanced, low-emission technology driveline entails thoroughly understanding typical truck operations in the real-world environment. This paper presents the work performed to develop a novel, more representative drayage duty cycle that characterizes drayage truck operations in the ports of San Pedro Bay in California. Unlike a conventional vehicle, an optimized hybrid driveline requires detailed understanding not only of torque requirements and vehicle speeds but also of the potential recovery of dynamic brake energy, charging opportunities, stopping and idling times, and many other operational requirements. Keeping this in mind, the duty cycle presented in this paper incorporated real-world, near-dock activities of Class 8 drayage trucks such as daily hours of operation, mileage, altitude profiles of routes, and idling and key-off patterns. The empirical duty cycle model was subsequently integrated with a complete vehicle simulation to explore the best solutions to minimize energy consumption for drayage applications in and around the ports. The analysis presented indicates that trucks spent most of the generated power in overcoming aerodynamic drag and rolling resistance of tires for a complete drayage shift and that electrical auxiliary loads dominated for near-dock operations because of idling and low-speed profiles. Therefore, achieving zero-emission near-dock operations entails focusing on auxiliary loads and rolling resistance. By using simulations, it was estimated that a hybrid truck with electrical power limited to about 100 kW could deliver a greenhouse gas emission reduction of about 30%.

Modernization of the Trailer for Tyre/Road Rolling Resistance Measurements

2011 ◽  
Vol 490 ◽  
pp. 179-186 ◽  
Author(s):  
Ryszard Woźniak ◽  
Stanislaw Taryma ◽  
Grzegorz Ronowski
Keyword(s):  
Laboratory Tests ◽  
Aerodynamic Drag ◽  
Rolling Resistance ◽  
Test System ◽  
Inertia Force ◽  
The Road ◽  
University Of Technology ◽  
On The Road ◽  
The Impact ◽  
Resistance Tests

In the article the ways of defining tyre rolling resistance are presented. The advantages of the laboratory tests of tyre/road rolling resistance and the advantages and the disadvantages of on the road tyre/road rolling resistance tests are described. The description of the special trailer used for tyre/road rolling resistance measurements designed and constructed in Faculty of Mechanical Engineering at Gdansk University of Technology is presented also. The trailer during it’s modernisation was equipped with special test systems which compensate the impact of disturbance factors such as: aerodynamic drag and inertia force acting on the tested tyre, slope of the road, tilt of the trailer and vibrations of the measuring arm. This article contains the description of only one compensation system applied in the measuring trailer which eliminates the aerodynamic drag. The conclusions which came from the measurements performed using this compensation test system are included.

CFD Analysis of Aerodynamic Drag Reduction in Heavy Vehicles by Changing its Frontal Area: Techinical Note

2019 ◽  
Vol 11 (5) ◽  
Author(s):  
D. Hasen ◽  
S. Elangovan ◽  
M. Sundararaj ◽  
K.M. Parammasivam
Keyword(s):  
Fuel Consumption ◽  
Aerodynamic Drag ◽  
Fuel Efficiency ◽  
Rolling Resistance ◽  
Aerodynamic Performance ◽  
Frontal Area ◽  
Heavy Vehicles ◽  
Design Engineers ◽  
Ansys Cfx ◽  
Aerodynamic Drag Reduction

Nowadays, fuel efficiency of heavy vehicles became an ultimate issue to the manufacturing and design engineers. The best approach to reduce the fuel consumption is to improve the aerodynamic performance of vehicle. This can be achieved by reducing the drag, because drag coefficient is directly proportional with the fuel consumption. Design engineers trying to improve the heavy vehicle’s performance by manipulating various parameters such as engine parameters, weigh, rolling resistance and aerodynamic drag. In this project, efforts were made to increase the aerodynamic performance by changing the frontal area of the container. Computational analysis was carried out at various velocities (50km/hr, 60km/hr, and 70km/hr) by changing the frontal area of the container in heavy vehicles. Different truck geometries were done using CATIA V5 and the simulations were done using ANSYS CFX software. Results were obtained and comparative studies were made. As a result of comparisons between various designs, the cowl of 2h dimension shows better results in reducing the drag when compared with the other designs.

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