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Video

The New Audi A6/A7 Family - Aerodynamic Development of Different Body Types on One Platform

2011-11-17
The presentation describes the aerodynamic development and optimization process of the three different new models of the Audi A6/A7 family. The body types of these three models represent the three classic aerodynamic body types squareback, notchback and fastback. A short introduction of the flow structures of these different body types is given and their effect on the vehicle aerodynamic is described. In order to achieve good aerodynamic performance, the integration into the development process of the knowledge about these flow phenomena and the breakdown of the aerodynamic resistance into its components friction- and pressure drag as well as the induced drag is very important. The presentation illustrates how this is realized within the aerodynamic development process at Audi. It describes how the results of CFD simulations are combined with wind tunnel measurements and how the information about the different flow phenomena were used to achieve an aerodynamic improvement.
Video

5000 Hours Aging of THERBAN® (HNBR) Elastomers in an Aggressive Biodiesel Blend

2012-05-23
TERBAN® hydrogenated nitrile rubber (HNBR) is a specialty elastomer used in demanding engineering applications such as the automotive, heavy duty, and industrial markets. It has excellent combination of heat, oil and abrasion resistance in addition to its high mechanical strength, very good dynamic and sealing properties. This paper will present data on aging HNBR for five thousand hours in an aggressive and un-stabilized B30A biodiesel fuel blend (70% ULSD, 30% SME, and an aggressive additive package) and explore the effect of HNBR polymer properties and vulcanizate composition on the performance in such fuel blends. Presenter Victor Nasreddine
Video

Development of Scratch Resistant Clear Coat for Automotive

2012-05-23
Scratch resistance is one of the most important customer requirements for automotive painting. Scratches occur as a result of a load being imposed on a paint film, which then destroys or deforms it. In order to improve the scratch resistance properties of clear coat, a specially developed molecular that act to accelerate closslinking reaction was added to the clear coat main resin. This developed molecular facilitates closslinking between multiple molecules and creates an unprecedentedly fine molecular structure. The result is a soft, highly elastic, and durable clear coat with improved resistance to light and acid as well as enhanced deformation recovery properties. It requires no special maintenance, prevents luster degradation caused by surface scratches and helps to prolong new-car color and gloss. Developmental Clear Coat is introduced into the flagship of the Lexus range - the LS as Self-restoring Coat in 2009. Presenter Junya Ogawa, Developmental Center
Video

Eco+ Solutions in High Performance Plastics from DSM for Automotive.

2012-05-22
DSM will present various application solutions in High Performance Plastics enabling to significant weight or friction reduction and thus to reduced fuel consumption and/or emission levels, and on top of that to lower system costs. Typical Eco+ Solutions Examples to be presented are: - Friction Reduction: Nylon 46 in chain tensioners yielding up to 1 % fuel reduction - Weight Reduction (metal-to-plastic conversion): Nylon 46 with long term temperature resistance upto 230 C in turbo components, Nylon 6 in oil pans/sumps, PET in plastic precision parts, Nylon 46 in gears, many other examples - Electrification: Nylon 46 in start/stop and e-motor components, TPC in HV cables - System Cost optimization: High Flow PA6 in various components, TPC in Brake Tubes - Improved LCA: biobased materials as PA410 and TPC-Eco Typical Application Solutions concern: air induction systems, engine and transmission components, electrical systems, structural&safety parts.
Video

Ice Phobic Coatings for Control and Covered Surfaces

2012-03-14
Silicones have been utilized in multiple industries in the last 50 years and their applications are still expanding as technology grows. Ice phobic coatings, as an example, have been utilized on lock walls, navigation channels, wind turbines, hydropower intakes, and aircraft. Without protection these applications have a high risk of failure in the functions they perform. For example, ice build up on an aircraft?s aerodynamic surfaces increases drag which reduces lift during flight operations. Utilizing a silicone ice phobic coating significantly reduces the adhesion of ice to aerodynamic surfaces. Compared to other polymeric materials, silicones are known for their broad operating temperature range and lend themselves to excellent performance in a variety of harsh environments. Especially in low temperatures where ice adhesion is a concern, silicones retain their elastomeric physical properties and low modulus.
Technical Paper

Development of a Single-Shoe Leading-Trailing Drum Brake—Code Named Fuchsia

2000-03-06
2000-01-0443
This paper describes a unique leading-trailing service drum brake design, code named Fuchsia, comprising a one-piece shoe and backing plate arrangement with an integral shoe platform. Because of the integral construction, Fuchsia offers a significant reduction in parts over the conventional drum brake design---it consolidates 16 standard components into one---resulting in a potential cost advantage over benchmarked products. It also offers benefits in performance stability, vibration resistance, low residual drag, low parasitic losses, and low operating threshold when compared to traditional designs. This paper gives an account of the key manufacturing processes, characteristics and performance testing of the brake and the incorporation of a extended-life lining configuration.
Technical Paper

The Transient Temperature Distribution in a Heavy Duty Brake System During Fatigue Crack Testing

2000-03-06
2000-01-0441
A transient numerical heat transfer model has been developed for the purpose of estimating the time-dependent temperature distribution in a heavy duty drum brake system. The model is based on a forward-difference explicit finite difference solution of the heat equation, in combination with a non-uniform pressure distribution for energy input, based on observed brake lining wear. Temperatures predicted by the model were compared to experimental dynamometer drum temperature measurements. The model was utilized to simulate a common industrial test for evaluation of brake drum resistance to thermo-mechanical fatigue cracking. Thermo-physical property variation and drum wall thickness were shown to exert a strong influence on the predicted temperature gradients and fatigue cracking susceptibility.
Technical Paper

Before and After Comparison of LRO and TV of Rotors After Low Temperature Gas Nitriding and Polymer Coat for Increased Corrosion Life

2000-03-06
2000-01-0446
Hayes Lemmerz has published in previous papers (Ref-1, 2 & 3), the method to low temperature nitride and polymer coat cast iron rotors to provide increased corrosion life, wear resistance and reduction in brake noise. We have, in this paper, investigated the two key dimensions of the rotor before and after the Nitriding Process. Low temperature (1050 degrees F) nitride finish machined rotors have to be handled in a special support fixture to prevent a change in thickness variation (TV) and lateral runout (LRO). Hayes Lemmerz has developed methods to keep LRO and TV in the print specification after the Nitriding and polymer coat process. The parts are made to extremely tight LRO and TV tolerances so that Nitriding done on such rotors, the dimensions of the rotors do not exceed print specification.
Technical Paper

Self Lubrication Type P/M Materials for the Lead Free Valve Seat

2000-03-06
2000-01-0395
Recent automotive engines are being produced with various types of fuel injection systems. One variation is the natural gas engine (LPG, CNG, etc. ) in which lubricating conditions become more severe than in conventional engines. Valve seats in such severe conditions require wear resistance. At the same time, automotive components are strictly regulated to exclude hazardous elements such as lead, a well known self lubricating element. New lead free materials have been developed for both inlet and exhaust valve seats. Some show better durability than lead infiltrated materials. For the purpose of heat and wear resistance, a tough matrix can be obtained from several types of homogeneously distributed alloy particles. Calcium fluoride ( CaF2 ) has also been found to provide a positive effect on wear resistance and self-lubrication.
Technical Paper

Properties of Precoated Galvannealed Steel Sheets for Lead-Free Automotive Fuel Tank Use

2000-03-06
2000-01-0307
The goal of this study was to identify a pre-coated steel sheet that will satisfy press formability, seam weldability, spot weldability, brazing property, external corrosion resistance and internal fuel resistance. We established an experimental method for anti-fuel resistance measurement by applying synthetic spoiled gasoline by investigating the composition of spoiled gasoline and corrosion products in the fuel tank, which was collected in North America after 160,000 kilometers' running. Newly developed lead-free pre-coated steel sheet shows excellent anti-fuel corrosion resistance in comparison with that of usual terne coated steel sheet according to this method.
Technical Paper

Bending Fatigue Properties of Prestrained Interstitial Free Zinc-Coated Sheet Steels

2000-03-06
2000-01-0309
The effects of prestrain and zinc coating type on the bending fatigue behavior of titanium-stabilized interstitial free steel were evaluated. From a single zinc bath chemistry, coated sheet steel samples were prepared with either a hot dip galvanized or galvannealed coating. Uniaxial tensile prestrains of 2 and 4 pct. were introduced parallel to the rolling direction on 12.7 cm wide strips. Krouse-type fatigue samples were machined both parallel and transverse to the rolling/prestrain direction. Reversed bending S-N fatigue data showed that the fatigue resistance depended on a complex interaction between the strength increase due to work hardening and fatigue crack development as altered by the presence of the coatings. For both coating types the fatigue resistance increased with prestrain. During prestrain, coating cracks oriented perpendicular to the tensile prestrain direction developed and the crack density was greater in the galvannealed materials.
Technical Paper

Modeling of Tire Rolling Properties by Using Experimental Modal Parameters

2000-03-06
2000-01-0361
An analytical tire model of freely-rolling properties is established by using experimental modal parameters. Based on force balance, rolling kinetics and road constrain conditions, the algorithms concerning deformation and force distribution within contact patch are derived, and structural damping is introduced in order to calculate rolling resistance under quasi-static state ( approximate to zero speed ). The derived model can describe the change process of vertical load and friction force distributions from static state to rolling state. Rolling resistance, effective rolling radius, slip ratio, and vertical stiffness of a freely-rolling tire are also calculated. The results are well consistent with literature. The rolling mechanism of tires is revealed and it is the basis for modeling of enveloping and cornering properties. The feasibility and advantages of tire modeling by using experimental modal parameters are reflected.
Technical Paper

A Flow Visualization Study of the Aerodynamic Interference Between Passenger Cars

2000-03-06
2000-01-0355
This research work is concerned with experimental studies of the aerodynamic interference between passenger cars. Aerodynamic interference covers the two cases of vehicles in a convoy and in parallel passing (overtaking). Vehicles are assumed to be moving in open roads. Flow visualization technique is used to clarify the flow behavior, especially wake structure behind interfering passenger cars. This paper is a trial to further explain the aerodynamic characteristics, usually reported in the form of pressure distributions and drag forces, through visible observations. Visualization images of passenger cars in close interference are presented for the first time. Special attention is paid to the effect of Reynolds number on flow pattern especially in severe interference conditions. Results show that flow structure around interfering cars changes dramatically depending on the gap between the cars and Reynolds number. Interesting flow structures are captured and analyzed.
Technical Paper

A New Aerodynamic Approach to Advanced Automobile Basic Shapes

2000-03-06
2000-01-0491
Aerodynamic basic shapes are generally intended as non wheeled bodies moving at a small distance from the ground, effective and suitable for automobile applications. The shape is furthermore designed to comply with requirements other than aerodynamic accomodating occupants, luggage and mechanical parts within as small as possible overall dimensions. However, even though the basic body drag coefficient can be as low as 0.05, the addition of wheels may increase the body drag, by two to three times. The new approach starts from the definition of aerodynamic criteria such as total lift close to zero, the pitching moment sign and value consistent with road holding and stability, a reduced sensitivity to side wind, gradual variation of the cross sections, etc..
Technical Paper

Rapid Aerodynamic Development of Two-Volume Vehicle Shapes

2000-03-06
2000-01-0488
The objective behind this effort is rapid aerodynamic development of vehicle themes, in the early stages of vehicle development. This paper describes a process that is suitable for the development of two-volume (or two-box) vehicle shapes (such as station wagons, minivans or sports utility vehicles). Traditionally, aerodynamic development at this stage is accomplished using wind-tunnel tests of full or partial scale test models or relying on simulations of aerodynamics employing computational fluid dyanmics (CFD). In either case, the process is not particularly effective in sustaining the desired level of communication between designers (engaged in styling activities) and engineers (engaged in packaging and aerodynamics). A key drawback here is the delay in the generation of aerodynamic drag estimates for the proposals under consideration through use of wind-tunnel tests or CFD computations.
Technical Paper

On the Underbody Flow of a Simplified Estate

2000-03-06
2000-01-0485
The demand for more energy efficient vehicles is driven by environmental considerations and alternative engine technology. In order to reduce fuel consumption on future vehicles the power needed to propel the car has to be lowered. Hence, considerable efforts are needed to improve the aerodynamics. For a modern vehicle the potential for further improvements on drag is mainly to be found in the underbody region, Howell (1991). This requires more knowledge of the underbody flow and the flow around the wheels. In the present work the flow in the underbody region has been studied using a combination of experiments and calculations to obtain a more comprehensive database. The model chosen for this work was the so called ASMO model from Daimler Benz, which is a well known geometry that is available for the public on the internet. A simple model was preferred since the goal was to study the basic mechanisms behind drag generated by the underbody flow.
Technical Paper

Creep and Bolt Load Retention Behavior of Die Cast Magnesium Alloys for High Temperature Applications: Part 2 of 2

2000-03-06
2000-01-1120
The effect of calcium on the creep and bolt load retention (BLR) behavior of AM50 alloy has been investigated. Four AM50 alloys 0, 0.25, 0.56, and 0.88% Ca have been die-cast. BLR-tests have been conducted at 125, 150, and 175°C and preloads of 14, 21, and 28kN. Tensile and compressive creep tests were also conducted at 150°C and initial stresses from 40 to 80 MPa. Both creep and BLR were significantly influenced by calcium content, with increasing calcium content resulting in improved relaxation resistance. The BLR of AM50 with 0.88% Ca was better than that of AE42 at all temperatures although the effect of calcium was temperature dependent. Calcium did not change the sensitivity of BLR to preload, while it increased the relaxation limit (Fr) of AM50 significantly. In addition, calcium improved the creep resistance of AM50 significantly.
Technical Paper

High Temperature-Creep Resistant Magnesium Alloys:Advances in Thixomolding Automotive Components

2000-03-06
2000-01-1126
Applications of magnesium-based alloys to transmission and underhood automotive components have been limited by creep and bolt-load relaxation. A further concern is the relative expense of Mg alloys, such as AE42, that contain rare earth elements. These alloys still fall short of the performance of 380 Al. A new family of low-cost Mg alloys (ZAC) containing Zn, Al, and Ca has been developed and reported to approach AE42 and to outperform 380 Al; however, it exhibits castability concerns in die casting. This study was designed to evaluate the performance of semi-solid injection-molded (Thixomolded®)1 ZAC8506 bolt-load retention samples at temperatures up to 175°C. The Thixomolding® process has been reported to markedly improve the creep resistance of AZ91D as the volume fraction of solids is increased. The processing conditions were selected to produce bolt-load retention samples having solid fractions of 6% to 37% primary alpha.
Technical Paper

Effect of Acid Modification for FRPP (Chopped Fiber Reinforced Polypropylene) on Creep Resistance Under Bending Loading at Elevated Temperature

2000-03-06
2000-01-1128
Creep tests under three-point bending loading were conducted at elevated temperatures for long glass fiber reinforced polypropylene in order to examine the effect of maleic anhydride modification for polypropylene matrix on the creep resistance. The high acid modification (1 wt%) significantly reduces the creep deflection at both low and high sustained loads. The residual tensile strength after 1000 hours creep also increased with an increase of maleic anhydride content. AE observation indicating an occurrence of debonding decreased with increasing acid density. The fractured surfaces show that the interfacial strength between glass fibers and matrix can be increased owing to an increase of maleic anhydride fraction.
Technical Paper

A Reduced Reaction Mechanism for Predicting Knock in Dual-Fuel Engines

2000-03-06
2000-01-0957
The present study extends our previous methane flame chemistry to methane autoignition based on most recent shock-tube experiments. It results in a detailed mechanism that consists of 128 elementary reactions among 31 species and that can be applied to predicting methane autoinginition times for temperatures between 1000 K and 2000 K, pressures between 1 bar and 250 bar and equivalence ratios between 0.4 and 3. A 9-step short mechanism is derived from this detailed mechanism with the objective of predicting knock in dual-fuel engines for equivalence ratio between 0.5 and 1.5 with temperature ranging 800 to 1200 K and pressure from 50 to 150 bar.
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