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Assuring continuous emission and fuel consumption standard compliance for vehicles in operation, a total production process for combustion engines has been developed, called original equipment remanufacturing. Utilizing over-sized dimensions, genuine spare parts and original factory specifications and tolerances, large quantities of exchange engines and cylinder head assemblies were already produced and installed into vehicles. In the course of the machining process some original standard dimensions are changed to over sizes (bores, pistons, rings, bearing shells, valve stems) or to under sizes (shaft journals, block height, cylinder head height, piston height). Dimensional changes may lead to changes in engine parameters like: cylinder volume, oil pressure, compression ratio, combustion process and emissions.

The paper presents two biaxial experimental strategies for describing the complex material behaviour of sheet metals. Experiments with wedge-shaped specimens subjected to tensile and compression stresses equivalent to deep-drawing conditions, and the biaxial tensile test with cruciform specimens, are used to emulate the two important cases of deep drawing and stretch forming. Their advantages and disadvantages are described. Finally, an allocation of the mechanical properties and typical forming processes is shown.

The dent resistance of a panel is an important consideration when selecting a type of steel for manufacturing. Yield strength, thickness of the formed part, and stiffness (related to curvature) of the panel each contribute to the overall denting behavior. This study examines the dent resistance of several grades of steel; the objective is to determine if a fundamental difference in denting behavior exists between bake hardenable and non-bake hardenable grades after normalizing with respect to yield strength and thickness in the panel. Several key parameters that may contribute to the denting process are examined, including effects of yield strength, strain aging, work hardening, and stiffness. In addition, an apparent strain-path dependence of yield point return has been observed in bake hardenable steels; the effect of this on dent resistance has yet to be determined.

This study deals with the development of high strength in a Low-Carbon Deep Drawing Quality Special Killed - Fully Stabilized steel sheet [DDQSK-FS (Interstitial Free type)] by a novel internal nitriding process. The unique feature of this method is that strength is imparted to cold rolled steel by a nitriding treatment after annealing without affecting its texture, resulting in a high strength drawable sheet. Strength of the generic Interstitial Free type sheet (stabilized with M = Ti, Nb or V) is increased by the controlled precipitation of coherent MN in ferrite, and the level of the strengthening can be predicted based on alloy chemistry and the nitriding conditions. Results of both laboratory and plant nitriding trials at U. S. Steel's (USS) Irvin Plant Open Coil Annealing Facility are presented.

The purpose of this paper is to discuss design methodology, manufacturing considerations, and testing proveout for a prototype gas-assist-molded, energy-absorbing, glovebox door program. The design used a single gas pin mounted in a multiple-gas-channel component and an internal gas manifold to form an efficient energy absorbing system. The end goal for the development program was to manufacture a glovebox door in a system that could meet the customer's targets for cost, surface appearance, and safety considerations without degrading function and fit. This paper will discuss the ability of a design methodology to predict actual component performance using engineering calculations, analytical tools, and prototype testing/molding during the development.

The energy dissipation behavior of foams depending on changes of loading rate input has been investigated and simulated to provide and guide a safe car interior design for occupant protection. However, all used foam models obtained from experiments at a specific loading rate could not represent general mechanical behavior of foam for various loading rates. In this study, a porous elastic theory was applied to investigate the effect of fluid phase on apparent rate dependent behavior in the elastic range of an open-cell foam. The porous elastic parameters of a polyurethane foam filled with air and liquid were measured and estimated using a new experimental method and reported data. Then, the porous elastic behavior of the foam in a uniaxial stress condition was simulated using the porous elastic parameters for various loading rates.

This paper describes the testing and constitutive model development of polyurethane foams for characterization of their material dynamic properties. These properties are needed not only for understanding their behavior, but also for supplying essential input data to foam models, which help provide design directions through simulations of foam selection for cushioning occupant head impacts against the vehicle door and upper interior. Polyurethane foams of varying densities were tested statically and dynamically under uniaxial compressive impact loading at constant velocities of various rates and different temperatures. The test results were utilized for developing a constitutive model of polyurethane foams by taking the density, strain rate and temperature effects into consideration. Uniaxial constitutive models are developed in two ways.

Automotive manufacturers must satisfy a myriad of criteria when selecting a polymer for interior trim applications. Additional challenges have been presented with the future phase-in requirements of Federal Motor Vehicle Safety Standard (FMVSS) 201U. This federal mandate requires vehicles to provide protection when an occupant's head strikes upper interior components such as thermoplastic pillars during an automobile crash. One limitation of FMVSS 201U is that it only prescribes performance requirements for simulated impact tests conducted at ambient test conditions. Many automobile crashes, however, occur at a multitude of vehicle temperatures. Moreover, thermoplastics are known to undergo a ductile to brittle transition whereby test specimens exhibit brittle failure upon impact at cold temperature. Therefore, reasonable engineering concern must be exercised to design robust systems that provide occupant protection across a wide range of test temperatures.

This paper will provide an overview of the “Fast Path” project which was designed to address the requirements of the new Federal Motor Vehicle Safety Standard (FMVSS) 201 Extended Rule, for automotive interior head impact protection. It will discuss the following topics: developing a system to identify successful combinations of materials and energy absorbing designs for automotive interior trim head impact applications, designing component testing and tooling, establishing a ranking methodology to provide engineering direction for future automotive products, and correlating to Finite Element Analysis (FEA) modeling.

A variety of energy absorbing foams were evaluated to address the Federal Motor Vehicle Safety Standard (FMVSS) 201 extended rule requirements for automotive interior head impact protection. The methodology used for the comparative study was the “Fast Path System” developed in part by Chrysler Corporation to provide a quick and reliable procedure to compare different materials and designs for energy management. Polyurethane, expanded polypropylene and expanded polystyrene energy absorbing foams were evaluated in this study.

The scratch resistance of automotive plastic coatings has been studied extensively over the past few years. Most testing methodology to correlate damage of the coating to field conditions has been in the form of small particulate wearing, e.g., alumina oxide abrasive, or indentation resistance of the coating to an external probe, e.g., a nanoindentation device. The subsequent damage imparted to the coating has generally been analyzed by the amount of coating mass lost in the wear event or through a ratio of optical reflectance of the damaged area to the undamaged surface. In this paper, we attempt to delineate surface damage resistance of several automotive clearcoats through an optical interferometry methodology developed to measure volume and depth of damage incurred with small particle alumina oxide erodents in a simulated wear environment.

The EPA of the Republic of China (Taiwan) will implement new emission regulations for 50-150 cc 2-stroke and 4-stroke motorcycles starting 1998. The exhaust emissions of motorcycles must be lower than 3.5 g/km CO and 2.0 g/km HC+NOx during the ECE-R40 driving cycle test. The emission legislation has a requirement for a catalyst durability life of 15,000 km. To comply with current legislation, the majority of 4-stroke motorcycles currently manufactured in Taiwan are fitted with secondary air systems, while 2-stroke motorcycles are fitted with catalytic converters. With this added equipment, 2-stroke and 4-stroke motorcycles generally can just achieve the emission targets when the motorcycles are new. However, it is an issue whether the exhaust emissions of motorcycles can meet the emission legislation after 15,000 km, because of the mass-production variation. This work presents some potential emission control strategies.

A cold-start partial oxidation (POX) system was integrated with a modern flexible fuel engine to assess its impact on cold-start performance and emissions. The POX reactor, a small combustion device operating fuel rich, converts liquid fuel into gaseous fuel species (reformate). The reformate from the reactor, when mixed with combustion air, replaces or supplements the standard fuel consumed during an engine start. This prototype integrated cold-start system has successfully reduced emissions from a cold-start on fuel grade ethanol (E95) at 5°C. The integrated POX system reduced the time-averaged hydrocarbon (HC) and carbon monoxide (CO) emissions by 80 and 40 percent, respectively. Starts on E95 reformate were achieved in less than 10 seconds at temperatures as low as -20°C.

Automobile and light truck interiors rely more and more on pre-assembled interior systems or modules, that may include trim components, lighting, electronics, wiring and fasteners, as received by the OEM assembly plant. In the case of the 1993 LH Headliner Module, an installation problem with the operators ergonomics at Chrysler's assembly plant required the same systems approach to the establishment of the root cause of the difficulty, as was applied to the design and development of the headliner module itself.

The substrate selection for headliner composites is driven by acoustics, systems integration, weight and cost considerations. However, the acoustical contribution of headliners plays a primary role in their design. This paper highlights the acoustical contribution of the various headliner composites. Various current headliner composites based on glass-fiber mat, polyurethane foam, resinated reclaimed fiber composites are considered. New composite structures are developed that exhibit good acoustical performance. The random incident acoustic evaluation is performed in an alpha-cabin which serves as a small reverberation room.

Many competitive headliner substrate materials were tested to determine the strengths and weaknesses of each material including new headliner materials such as those on the 97 Ford Expedition, 96 Chevrolet Cavalier, 97 GM G Van, 96 Ford Contour, and 96 Chrysler Cirrus, all of which are urethane/foam/glass layered substrates and the 96 Nissan Altima, a corrugated cardboard base substrate. In general, today's headliners are based upon three substrate types glass, foam, or cellulose (paper or cotton). Glass headliners are requested less frequently due to the lack of recycleability and the skin irritation caused to assembly plant workers. Of those substrate candidate materials screened, the best performing headliner substrate materials were 1997 Ford Expedition and 1997 GM G Van.

Recycling of automotive headliners has been carried out by grinding them and forming composites with isocyanate-based binders. Rear-seat-to-back-window trim panels have been prepared. Composites with 80-90 wt.% of scrap manufactured in plant runs exhibited mechanical properties comparable to the existing products. The rear-seat-to-back-window trim panel composites were produced by compression molding ground scrap-binder pre-preg sheets for 30 seconds at moderate temperatures, with no postcuring. This is the best indication that the utilization of the scrap headliners is both technically and economically sound. The plant runs have confirmed the feasibility of production of large parts with relatively complex shapes such as headliners. The adhesion of decorative materials to the composite substrates was excellent. More importantly, the decorative materials can be applied to the substrate during compression molding without any additional adhesive.

Layered structures made from elastic and porous materials are widely used as insulation systems in the automotive industry. They have a dynamic behavior which is strongly influenced by the various interaction mechanisms within the porous material. The paper concentrates on modeling such materials using a 3-D finite element (FE) approach. This model can be combined with a boundary element (BE) procedure in order to assess the radiated acoustic field. The key part of FE representation is a Biot's model for the two phase porous material. A mixed displacement formulation is selected. The model can be used for predicting the surface impedance and/or the acoustic transmission characteristics of layered materials. The combined use of this mixed FE/BE model enables also the evaluation of the acoustic response (radiated power, field pressure).

The effects of strain rate on the deformation behavior of steels were investigated to find the most appropriate micro structure of steel for anti-crash parts of automobiles, such as front-side-members. The dual phase steel absorbed a higher amount of energy during dynamic deformation than other steel with the same static yield strength. The increase of volumetric fraction of the austenite phase in the dual phase steel deteriorates the dynamic deformation behavior. The FEM analysis for crash test of member also showed the superior performance of the dual phase steel.

Headliner technology will be presented in this paper. Older established technologies such as cut & score, fiberglass, hardboard and resinated cotton are still used because of their proven reliability and low cost. But newer processes including polyester, natural fiber, Tramivex™ and urethane offer reliability, structure, acoustic performance and some recyclability. Fiberglass has always been a leader in acoustical performance but has breakage and handability issues in the assembly plants. This paper will be divided in four sections. The first section discusses manufacturing processes for headliners covering current and past. It also covers the materials used and types of facing. This section will state why headliner technology used in the USA is different than Europe or emerging markets. Second section describes acoustics. It will explain performance as related to material types. Porosity, cell type, fiber length and diameter is explained as it relates to the absorption of sound.