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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.
Standard

Guidelines for Aerodynamic Assessment of Mass-Produced Cars and Light-Duty Trucks Using Computational Fluid Dynamics

2019-07-01
WIP
J3191
This document outlines general requirements for the use of Computational Fluid Dynamics (CFD) methods for aerodynamic simulation of mass-produced cars and light-duty trucks. The document provides guidance for aerodynamic simulation with CFD methods to support current vehicle characterization, vehicle development, vehicle concept development and vehicle component development. The guidelines presented in the document include Navier-Stokes and Lattice-Boltzmann based solvers.
Standard

In-truck manufacturing of SAE Type I Aircraft Deicing Fluid

2019-10-29
WIP
ARP6677
This SAE Aerospace Recommended Practice (ARP) covers requirements for in-truck manufacturing of SAE AMS1424 Type I deicing/anti-icing fluid, and contains technical and other requirements which apply to the in-truck manufacturing of Type I deicing/anti-icing fluid
Technical Paper

Surface Treatments and Characterization of Electroplated and Hot Dip Galvanized Steel Sheets

1996-04-01
91A126
Protection of surfaces is a critical factor in determining the extended service life of a structure in polluted and aggressive environments. In particular, a rapid growth of the technology for the protecting coating of cold rolled steel is experienced, for the use in transport, electric housewares, building and industrial plants. Numerous changes have taken place in the production of zinc coatings on steel in order to improve the corrosion resistance using zinc alloy platings. Our research group collected from the international production a number of selected galvanized steel samples, including electrodeposited zinc alloys, multilayer coatings, hot dip galvanized steels. On the selected materials we established and analyzed morphology, composition, crystal structure, impurity content and distribution, using many surface microanalysis techniques.
Technical Paper

Thermomechanical Behavior and Wear Resistance of Whisker Or Particle Reinforced Ceramics

1996-04-01
91A107
Ceramic composite materials have been intensively studied during the last years. Particles and whisker reinforcement have shown the simultaneous advantage to allow the preparation of composite materials by conventional processing and to lead, when under optimum conditions, to dramatic toughening and strengthening. Since wear resistance of brittle material have been shown to be related to both hardness and toughness, composite materials with improved were resistance have been developed for cutting tools or bearing applications. However the mechanism responsible for toughening is of major important for wear resistance effectiveness. We have therefore reviewed the main mechanisms before presenting some examples of composites materials for wear resistance applications.
Technical Paper

Manufacture of Automotive Components By Semi-Liquid Forming Process

1996-04-01
91A113
Semi-liquid forming process, applied to pressure die-casting, permits to obtain low cost components with high qualitative characteristics and adequate mechanical performances. The technology is based on the employment of material with globular microstructure (flow-cast alloys) obtained subjecting a metal alloy at the time of solidification to an elevated shear rate. Such microstructure permits the accomplishment of conventional forming processes at temperatures in solidification range. The particular fluid-dynamic properties of the semi-liquid slurry and the lower injection temperature allow to obtain casting with improved soundness, without need of impregnation, and to extend die life. The present work describes the Weber (Magneti Marelli) activity of the process industrialization and some applications for the manufacture of automotive components.
Technical Paper

Casting and Characterization of An Aluminum Alloy Car Engine Bracket Produced By Squeeze Casting Technology

1996-04-01
91A114
The following paper describes the experimental activity regarding the setting-up and characterization of a car engine bracket in Al-Si12Cu2FeZn-F alloy produced by the new technology squeeze casting. LExperimentation was carried out at the Alures squeeze casting pilot plant. Static and dynamic characterization (fatigue resistance on test samples and the component itself) was carried out at Teksid and Fiat Auto. Characterization test have demonstrated the considerable advantages offered by the new technology compared with conventional production processes.
Technical Paper

Critical Issue Relating to the Quality of Properties Data

1996-04-01
91A091
The generation of properties data on plastics falls short of what the designers and producers of end-products would prefer. The fundamental causes of this mismatch are examined and possible corrective actions are proposed with some data on impact resistance given to illustrate key points.
Technical Paper

Correlation of Bending Strength and Errors of Helical Gear

1988-03-01
871223
CORRELATION OF BENDING STRENGTH AND ERRORS OF HELICAL GEAR has not been clarified sufficiently even now. As the investigation by using only experimental method is not sufficient and so the analytical method of obtaining gear bending strength has been developed by one of the authors. Hence, the correlation of bending strength and errors, especially in the aspect of the direction of pressure angle error and tooth trace error, is clarified by this analytical method which was verified by some experiments. And by further investigations, it is confirmed that the helical gear is tougher against the negative pressure angle error, and the fine module gear is sensitive against the errors.
Technical Paper

Tire/Pavement Interaction Noise Source Identification Using Multi-Planar Nearfield Acoustical Holography

1999-05-17
1999-01-1733
In this study, multi-planar Nearfield Acoustical Holography (NAH) is used to investigate noise radiated from the front, side and rear areas of single tires on a two-wheel trailer. Contributions to the radiated noise from the leading edge, trailing edge, and sidewall of the tire are identified. Two tires - an experimental monopitch tire and a production passenger car tire - are evaluated on a smooth asphalt pavement at 58 km/hr. From the measured complex pressure, acoustic intensity is reconstructed on three planes surrounding the tire using modified NAH procedures. Additionally, sound power levels are presented in tabulated and spectra forms. Tire noise generating mechanisms are inferred based on the results.
Technical Paper

Noise Analysis of Automotive Alternators

1999-05-17
1999-01-1712
An extensive experimental study of noise generating mechanisms of two production models of automotive alternators is presented. It was established that aerodynamic noise (generated by cooling fans) is dominating at high speeds (above 3,000 rpm), while electromagnetic noise is the most intensive at low rpm. Two directions of noise reduction are proposed and validated: reduction of noise levels generated by alternators to be achieved by using axial flow fans for cooling instead of presently used bladed discs, and radical reduction of operating speed of alternators by using variable transmission ratio accessory drives.
Technical Paper

Detection of Icing and Related Loss of Control Effectiveness in Regional and Corporate Aircraft

1999-04-20
1999-01-1583
This paper presents a method of detecting aircraft icing by monitoring its effects on aircraft dynamics. This paper shows that uncontrolled icing on control surfaces directly influences control effectiveness. Using data from onboard attitude and navigation sensors via highly computationally efficient algorithms, the control effectiveness is estimated, thereby detecting icing. Using actual flight test data from NASA Lewis Research Center, this paper demonstrates the ability of this method to detect the loss of elevator effectiveness that occurs with uncontrolled horizontal stabilizer icing that could result from a failed deicing boot. The method is generally applicable to loss of control effectiveness due to icing. Icing affects the aerodynamic performance of aircraft by contaminating the aerodynamic surfaces. Without anti-icing equipment icing, if sufficiently severe, can relatively quickly lead to a situation in which controllable flight is impossible.
Technical Paper

Transfer Matrix Approach to the Estimation of the Fundamental Acoustical Properties of Noise Control Materials

1999-05-17
1999-01-1667
A new method for evaluating the acoustical properties of porous materials is described here. To implement the procedure, a two-microphone standing wave tube was modified to include: a new sample holder; a section that accommodated a second pair of microphones downstream of the sample holder; and an approximately anechoic termination. A four-point sound pressure method was then used to estimate the two-by-two transfer matrix of the material. The transfer matrix can then be used to determine the wave number and characteristic impedance of the material. The procedure has been used to estimate the acoustical properties of two glass fiber materials.
Technical Paper

Acoustical Advantages of a New Polypropylene Absorbing Material

1999-05-17
1999-01-1669
Sound absorption is one way to control noise in automotive passenger compartments. Fibrous or porous materials absorb sound in a cavity by dissipating energy associated with a propagating sound wave. The objective of this study was to evaluate the acoustic performance of a cotton fiber absorbing material in comparison to a new polypropylene fibrous material, called ECOSORB ®. The acoustical evaluation was done using measurements of material properties along with sound pressure level from road testing of a fully-assembled vehicle. The new polypropylene fibrous material showed significant advantages over the cotton fiber materials in material properties testing and also in-vehicle measurements. In addition to the performance benefits, the polypropylene absorber provided weight savings over the cotton fiber material.
Technical Paper

A New Light Weight, High Performance, Spray Applied Automotive Damping Material

1999-05-17
1999-01-1674
A new multifunctional material was developed to provide corrosion protection, anti-chip protection and vibration damping equal to or better than the existing materials today. This multifunctional coating, applied robotically or manually with airless spray equipment, is a one component system and provides the following characteristics: high vibration damping, low viscosity-easy to process, low shrinkage-no small molecules given off, no solvents, excellent adhesion to oily steel and electrocoat, excellent stone-chip resistance, high stiffness and low density. This paper describes the application and performance benefits of utilizing this sprayable, chip-resistance damper.
Technical Paper

Reconstruction of the Cylinder Pressure from Vibration Measurements for Prediction of Exhaust and Noise Emissions in Ethanol Engines

1999-05-17
1999-01-1658
There are growing demands for condition monitoring of IC engines, and therefore any method in order to improve the performance of the engines ought to be evaluated. This paper proposes a new approach for the prediction and optimisation of noise and exhaust emissions in IC engines. The idea is to reconstruct the cylinder pressure from vibration measurements on the engine surface by using the complex cepstrum method [3, 4]. The reconstructed cylinder pressure is further used as input in Multivariate models, based on cylinder pressure, for estimating noise and exhaust emissions. This paper demonstrates the applicability of the method for modelling of noise and exhaust emissions
Technical Paper

Durability, Acoustic Performance and Process Efficiencies of Absorbent Fibers for Muffler Filling

1999-05-17
1999-01-1655
Silencers are very often filled with absorbent fibers to optimize the acoustic performance, particularly when the volume is limited. The fibers have to meet several specifications concerning (1) acoustic damping as a function of frequency, (2) temperature stability, (3) processing, and (4) blow-out resistance. This paper will review the characteristic properties for continuous fibers including Advantex™ versus standard E Glass as well as discontinuous fibers such as basalt wool. The failure mechanism of the various fibers will be explored in detail. Thermal shock testing, single filament tensile strengths, and weight loss measurements will be used to contrast the failure mechanism of these fibers. Additionally, the acoustic performance of silencers filled with different fibers will be analyzed and compared. The selection of different filling materials is closely linked to the production process utilized.
Technical Paper

Effect of High Squish Combustion Chamber on Simultaneous Reduction of NOx and Particulate from a Direct-Injection Diesel Engine

1999-05-03
1999-01-1502
In this study it is tried to reduce NOx and particulate emissions simultaneously in a direct injection diesel engine based on the concept of two-stage combustion. At initial combustion stage, NOx emission is reduced with fuel rich combustion. At diffusion combustion stage, particulate emission is reduced with high turbulence combustion. The high squish combustion chamber with reduced throat diameter is used to realize two-stage combustion. This combustion chamber is designed to produce strong squish that causes high turbulence. When throat diameter of the high squish combustion chamber is reduced to some extent, simultaneous reduction of NOx and particulate emissions is achieved with less deterioration of fuel consumption at retarded injection timing. Further reduction of NOx emission is realized by reducing the cavity volume of the high squish combustion chamber. Analysis by endoscopic high speed photography and CFD calculation describes the experimental results.
Technical Paper

The Autoignition Behavior of Surrogate Diesel Fuel Mixtures and the Chemical Effects of 2-Ethylhexyl Nitrate (2-EHN) Cetane Improver

1999-05-03
1999-01-1504
The oxidation of surrogate diesel fuels composed of mixtures of three pure hydrocarbons with and without their cetane numbers chemically enhanced using 2-ethylhexyl nitrate (2-EHN) is studied in a variable pressure flow reactor over a temperature range 500 - 900 K, at 12.5 atmospheres and a fixed reaction time of 1.8 sec. Changes in both low temperature, intermediate temperature, and hot ignition chemical kinetic behavior are noted with changes in the fuel cetane number. Differences appear in the product distribution and in heat release generated in the low and intermediate temperature regimes as cetane number is increased. A chemically enhanced cetane fuel shows nearly identical oxidation characteristics to those obtained using pure fuel blends to produce the enhanced cetane value. The decomposition chemistry of 2-EHN was also studied. Pyrolysis data of 10% 2-EHN in n-heptane and toluene are reported.
Technical Paper

A Non-Averaging Method of Determining the Rheological Properties of Traction Fluids

1999-05-03
1999-01-1518
Traction machines have been frequently used to study the rheological properties of lubricants in elasto-hydrodynamic lubrication (EHL) contacts. Fundamental properties are inferred from EHL traction measurements based on the average pressures and temperatures in the contact. This average approach leads to uncertainty in the accuracy of the results due to the highly nonlinear response of fluid rheological behavior to both pressure and temperature. A non-averaging method is developed in this paper to determine the elastic and plastic properties of traction fluids operating in EHL contacts at small slide-to-roll ratios. A precision line-contact traction rig is used to measure the EHL traction at a given oil temperature and Hertz pressure. By choosing a sensible pressure-property expression, the parameters of the expression can be determined through the initial slope and peak traction coefficient of the traction measurements.
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