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Multi-Chamber Tire Concept for Low Rolling-Resistance
Aldhufairi H.S., Essa K., Olatunbosun O.
Q3
SAE International Journal of Passenger Cars - Mechanical Systems,
2019,
цитирований: 5,
doi.org,
Abstract
Rolling-resistance is leading the direction of numerous tire developments due to its significant effect on fuel consumption and CO2 emissions considering the vehicles in use globally.Many attempts were made to reduce the rolling-resistance but with no gain or limited success due to the tire complexity and the trade-offs.This paper investigates the concept of multiple chambers inside the tire as a potential alternative solution for reducing the rolling-resistance.To accomplish that, novel multi-chamber designs were introduced and numerically simulated through finite-element (FE) modeling.The FE models were compared against a standard design as the baseline.The influences on rolling-resistance, grip, cornering, and mechanical comfort were studied.The multi-chambers tire reduced rollingresistance considerably with acceptable trade-offs.Independent air volumes isolating tread from sidewalls would maintain tire's profile effectively.Different air concentration across tire's chambers gave the tire extended versatility.Rolling non-uniformity depends upon inner-chambers' stability, sidewalls' flexibility and tire/chamber(s) integration.
Aerodynamic Analysis of Grand Prix Cars Operating in Wake Flows
Newbon J., Sims-Williams D., Dominy R.
Q3
SAE International Journal of Passenger Cars - Mechanical Systems,
2017,
цитирований: 10,
doi.org,
Abstract
The effect of the upstream wake of a Formula 1 car on a following vehicle has been investigated using experimental and computational methods.Multiple vehicle studies in conventional length wind tunnels pose challenges in achieving a realistic vehicle separation and the use of a short axial length wake generator provides an advantage here.Aerodynamic downforce and drag were seen to reduce, with greater force reductions experienced at shorter axial spacings.With lateral offsets, downforce recovers at a greater rate than drag, returning to the level for a vehicle in isolation for offsets greater than half a car width.The effect of the wake was investigated in CFD using multiple vehicle simulations and non-uniform inlet boundary conditions to recreate the wake.Results closely matched those for a full two-vehicle simulation provided the inlet condition included unsteady components of the onset wake.Creating a nonuniform inlet condition allowed the wake parameters to be modified to test sensitivity to different wake features.Dynamic pressure deficit in the wake is shown to have the greatest impact on the following vehicle, reducing loading on the downforce producing surfaces.Wake up-wash and vortex flows are shown to have a smaller effect on downforce generated by the following car, but have an important role in diverting the dynamic pressure deficit upwards and over the following car.Future regulation changes, aimed at reducing the downforce loss experienced when following another car, should aim to reduce the velocity deficit onset to the following car; either by reducing wheel and underbody wakes, or by extracting the wake using up-wash from the rear wing.
Coupled Level-Set Volume of Fluid Simulations of Water Flowing Over a Simplified Drainage Channel With and Without Air Coflow
Dianat M., Skarysz M., Hodgson G., Garmory A., Passmore M.
Q3
SAE International Journal of Passenger Cars - Mechanical Systems,
2017,
цитирований: 9,
doi.org,
Abstract
The motivation for this paper is to predict the flow of water over exterior surfaces of road vehicles.We present simulations of liquid flows on solid surfaces under the influence of gravity with and without the addition of aerodynamic forces on the liquid.This is done using an implementation of a Coupled Level Set Volume of Fluid method (CLSVOF) multiphase approach implemented in the open source OpenFOAM CFD code.This is a high fidelity interface-resolving method that solves for the velocity field in both phases without restrictions on the flow regime.In the current paper the suitability of the approach to Exterior Water Management (EWM) is demonstrated using the representative test cases of a continuous liquid rivulet flowing along an inclined surface with a channel located downstream perpendicular to the oncoming flow.Experimental work has been carried out to record the motion of the rivulet in this case and also to measure the contact angle of the liquid with the solid surface.The measurements of the liquid/solid characteristics such as equilibrium and dynamic contact angles are described along with the analytical expression for contact angle vs. capillary number used in the CFD code.The results from the simulations are compared to experimental measurements.The simulations are carried out with air co-flows of 0, 0.5 and 10 m/s.The simulations are seen to reproduce physical phenomena such as the liquid pinning at sharp corners and the longitudinal stretching of the rivulet with higher air velocity.
A Parametric Study of Automotive Rear End Geometries on Rear Soiling
Kabanovs A., Hodgson G., Garmory A., Passmore M., Gaylard A.
Q3
SAE International Journal of Passenger Cars - Mechanical Systems,
2017,
цитирований: 12,
doi.org,
Abstract
The motivation for this paper is to consider the effect of rear end geometry on rear soiling using a representative generic SUV body.In particular the effect of varying the top slant angle is considered using both experiment and Computational Fluid Dynamics (CFD).Previous work has shown that slant angle has a significant effect on wake shape and drag and the work here extends this to investigate the effect on rear soiling.It is hoped that this work can provide an insight into the likely effect of such geometry changes on the soiling of similarly shaped road vehicles.To increase the generality of results, and to allow comparison with previously obtained aerodynamic data, a 25% scale generic SUV model is used in the Loughborough University Large Wind Tunnel.UV doped water is sprayed from a position located at the bottom of the left rear tyre to simulate the creation of spray from this tyre.Having a single source of contamination simplifies the configuration of both experimental tests and simulations.It also improves analysis by allowing the soiling pattern from only one wheel to be seen in isolation.In order to provide further insight into the flowfield and its interaction with the spray CFD simulations are also performed at the same scale.A Detached Eddy Simulation approach is used, specifically the Spalart Allmaras formulation of the IDDES CFD model.Lagrangian particle tracking is used to model the dispersed phase.This CFD methodology has been found to give good agreement for soiling pattern with experiment for baseline cases.
Aerodynamic Investigation of Cooling Drag of a Production Sedan Part 1: Test Results
Larson L., Woodiga S., Gin R., Lietz R.
Q3
Aerodynamic Investigation of Cooling Drag of a Production Sedan Part 2: CFD Results
Larson L., Gin R., Lietz R.
Q3
Predicted Machining Dynamics for Powertrain Machining
Ziada Y., Yang J., DeGroat-Ives D.
Q3
Durability Loads Prediction of Body-on-Frame Vehicles using Full Vehicle Simulations
Roy N., Scheiblegger C., Darling J., Pfeffer P.
Q3
Efficiency and Durability Predictions of High Performance Racing Transmissions
Fatourehchi E., Elisaus V., Mohammadpour M., Theodossiades S., Rahnejat H.
Q3
SAE International Journal of Passenger Cars - Mechanical Systems,
2016,
цитирований: 16,
doi.org,
Abstract
Efficiency and durability are key areas of research and development in modern racing drivetrains.Stringent regulations necessitate the need for components capable of operating under highly loaded conditions whilst being efficient and reliable.Downsizing, increasing the powerto-weight ratio and modification of gear teeth geometry to reduce friction are some of the actions undertaken to achieve these objectives.These approaches can however result in reduced structural integrity and component durability.Achieving a balance between system reliability and optimal efficiency requires detailed integrated multidisciplinary analyses, with the consideration of system dynamics, contact mechanics/tribology and stress analysis/structural integrity.This paper presents an analytical model to predict quasi-static contact power losses in lubricated spur gear sets operating under the Elastohydrodynamic regime of lubrication.Tooth Contact Analysis (TCA) is used to predict variations in contact loads, local surface curvature and rolling and sliding velocities.This is combined with an extrapolated oil film thickness formula available in literature, to predict instantaneous lubricant film thickness and sub-surface stresses.Subsequently, viscous and boundary friction are estimated, enabling calculation of power losses.The presented methodology has been used to investigate the effects of parabolic tip relief on power loss and induced sub-surface stresses.The results of this investigation are also presented.
Understanding the Fundamentals of Boxer Engine Behavior on Sound Quality
Deighan T., Kato N., Sato K.
Q3
Piston Design for Optimizing Trade-off of Friction and NVH
Jay A., Deighan T., Kato N., Sato K.
Q3
A Fully Coupled, 6 Degree-of-Freedom, Aerodynamic and Vehicle Handling Crosswind Simulation using the DrivAer Model
Forbes D.C., Page G.J., Passmore M.A., Gaylard A.P.
Q3
SAE International Journal of Passenger Cars - Mechanical Systems,
2016,
цитирований: 28,
doi.org,
Abstract
In a real-world environment, a vehicle on the road is subjected to a range of flow yaw angles, the most severe of which can impact handling and stability.A fully coupled, six degrees-of-freedom CFD and vehicle handling simulation has modelled the complete closed loop system.Varying flow yaw angles are introduced via time dependent boundary conditions and aerodynamic loads predicted, whilst a handling model running simultaneously calculates the resulting vehicle response.Updates to the vehicle position and orientation within the CFD simulation are achieved using the overset grid method.Using this approach, a crosswind simulation that follows the parameters of ISO 12021:2010 (Sensitivity to lateral wind -Open-loop test method using wind generator input), was performed using the fastback variant of the DrivAer model.Fully coupled aerodynamic and vehicle response was compared to that obtained using the simplified quasi-steady and unsteady, one way coupled method.Between the quasi-steady and unsteady simulations, an overshoot in aerodynamic yaw moment for the latter resulted in a larger lateral deviation of approximately 8%.However, the differences in responses between the transient, one-way and fully coupled methods were small for this particular geometry.It is expected that by increasing gust length, differences will appear, as the vehicle is exposed to the larger flow yaw angle for a longer period.
Technical Analysis of a Proposed Shock Absorber Design Standard
Tandy D.F., Hanba S., Pascarella R.
Q3
Quantifying Hands-Free Call Quality in an Automobile
Amman S., Charette F., Nicastri P., Huber J., Richardson B., Puskorius G., Gur Y., Cooprider A.
Q3
Base Pressure and Flow-Field Measurements on a Generic SUV Model
Wood A., Passmore M., Forbes D., Wood D., Gaylard A.
Q3
SAE International Journal of Passenger Cars - Mechanical Systems,
2015,
цитирований: 16,
doi.org,
Abstract
The pressure on the base of a vehicle is a major contributor to the aerodynamic drag of all practical vehicle geometries, and for some vehicles, such as an SUV, it is particularly important because it can account for up to 50% of the overall drag.Understanding the mechanisms that influence the base pressure and developing our simulation tools to ensure that base pressure is accurately predicted are essential requirements for the vehicle design and engineering process.This paper reports an experimental study to investigate the base pressure on a specifically designed generic SUV model.The results from ¼ scale wind tunnel tests include force and moment data, surface pressures over the base region and particle image velocimetry (PIV) in the wake.Results are presented for the vehicle in different ride height, underfloor roughness and wheel configurations and the paper includes some description of the experimental errors.Some initial CFD simulations are also reported.
CFD Investigation of the Effect of the Salient Flow Features in the Wake of a Generic Open-Wheel Race Car
Newbon J., Dominy R., Sims-Williams D.
Q3
SAE International Journal of Passenger Cars - Mechanical Systems,
2015,
цитирований: 12,
doi.org,
Abstract
It is well known that in motorsport the wake from an upstream vehicle can be detrimental to the handling characteristics of a following vehicle, in particular in formulae with high levels of downforce.Previous investigations have been performed to characterize the wake from an open wheel race car and its effect on a following car, either through the use of multiple vehicles or purpose-built wake generators.This study investigates how the wake of an upstream race car impacts the aerodynamic performance of a following car in a close-following scenario.Wakes are imposed on the inlet of a CFD simulation and wake parameters (eg: velocity deficit, trailing vorticity) are directly manipulated to investigate their individual impacts on the following vehicle.The approach provides a useful alternative to the simulation of multi-vehicle cases but a better simulation could be achieved by including wake unsteadiness from the upstream vehicle.Arguably the most significant impact of a wake on the following vehicle was found to be the rearward movement of the vehicle center of pressure.Secondary flow (eg: upwash, vorticity) on a bulk scale had the beneficial impact of moving the wake up and over the following vehicle but more localized impacts could be positive or negative according to the detailed interaction with downstream vehicle features.
CAE-Based Driving Comfort Optimization of Passenger Cars
Drotar T., Palandri J., Wolf-Monheim F., Zandbergen P., Reff B.
Q3
SAE International Journal of Passenger Cars - Mechanical Systems,
2015,
цитирований: 2,
doi.org,
Abstract
Excellent vehicle dynamics performance has strongly contributed to the appealing driving experience of Ford vehicles. This is achieved via application of advanced suspension concepts, high structural stiffnesses of body and chassis components and extensive tuning work on the vehicle proving grounds. One of the key challenges in vehicle engineering is to optimize vehicle driving comfort without degrading the steering and handling performance.
A Study into Compression Ring Dynamics using Response Surface Methodology
Dickinson M.W., Renevier N., Calderbank J.
Q3
SAE International Journal of Passenger Cars - Mechanical Systems,
2015,
цитирований: 1,
doi.org,
Abstract
For decades the operational dynamics of the compression ring during operation, have been subject to debate [1,2,3,4,5,6,7].A complex computer simulation, using Design Of Experiments (DOE) methodology, was developed to study the effect of the compression ring rotation during running-in stages.Response Surface (RS) has been used to optimize ring displacement, as function of ring mass, width and radius.The optimised surface response has been compared to used compression rings and has shown a 2% variation between calculated and measured values.
Influence of Test Procedure on Friction Behavior and its Repeatability in Dynamometer Brake Performance Testing
Grochowicz J., Agudelo C., Li S., Abendroth H., Wollenweber K., Reich A.
Q3
Discrete Flow Mapping - A Mesh Based Simulation Tool for Mid-to-High Frequency Vibro-Acoustic Excitation of Complex Automotive Structures
Tanner G., Chappell D.J., Löchel D., Søndergaard N.
Q3
