Mold designers and foundrymen spend a lot of time in developing molds without knowing exactly the phenomena which take place inside. Simulor, which has been used in an industrial environment for two years, offers the solution to make foundrymen understand what happens during the filling of the mold and the solidification of the part. Based on navier-stokes and heat transfer equations, simulor provides speed distribution and metal front evolution in the cavity and thermal map in the mold and the part. Some examples with different metals (cast iron, aluminum alloy) cast with various processes (sand or die casting, low pressure or gravity casting) will be given. This new tool will given foundrymen the opportunity to test the mold before having it machined and will also allow reduction in development delays.
In the present paper we will outline the principles, designs, problems and benefits of electrochromic coatings and present our own laboratory results. The effect of electrochromic coatings on the thermal comfort of a parked vehicle is theoretically calculated and the results confronted with the performances of selective coatings.
The windows of a vehicle have to satisfy the following driver and passenger needs concerning visibility and climate perception both related to active safety: transparency, reluctance, dazzling, glare and diffused light (scattering). All functions are related to visibility and so to the optics of glazing, solar control, deicing, defogging, demisting. The task of material science is to find the multifunctional glasses solving simultaneously problems of visibility, safety and comfort. Particular kind of glasses, colored, wired, coated, electrochromic, liquid crystal, photochromic can be already considered solutions which can operate passively or actively. The example of passive solar control and active heatable coated glasses is shown as a possible practical multifunctional glass very soon.
The pending changes in European law enabling the use of plastic lenses on vehicle headlamps provide an opportunity for further advancement of vehicle styling, lighting performance and aerodynamic efficiency. Plastic lenses can also provide a useful weight saving and contribute to energy savings during the lifetime of the vehicle. This paper discusses the current requirements, technologies and solutions for plastic lenses, and indicates the way this advance can impact on the evolution of lighting products.
The paper review some recent efforts, made by the aluminum industry, towards the development of new advanced alloys for aerospace applications; unconventional production technologies and MMC occupy an outstanding position in this context. Raid solidification processes are currently used for obtaining advanced alloys and, among them, the powder metallurgy route is one of the most commonly applied, since it has reached a considerable level of maturity. Experimental results of PM materials are shown and discussed in order to appreciate the potentialities of this class of materials and some recent further progress is shown: the spray deposition approach (osprey process). After having described the main features of the osprey process, some results obtained at the Department of Aerospace Engineering of Pisa about the development of high strength Al-alloy and MMC obtained by means of the osprey process are shown.
An overview of high strength thermoset and thermoplastic composites will provide a basis of comparison with exotic hybrid composites. A specific theoretical application for a very high strength unibody application will be presented and test results evaluated. A critical overview of immediate applications will be presented and evaluated. In conclusion, it will be suggested that a uniform standard of performance be established for the practical application's requirements for these materials
Predictable and unpredictable forces will change the direction of the charge-air systems industry. The driver of diesel engine development will be the stringent emissions regulations of the 1990s. The drivers in the gasoline engine market will be improved fuel economy, performance, durability and emissions. Forces will also influence the charge-air marketplace, including changes in emission standards, national fiscal policies, political issues, fuel prices, alternate fuels and consumer tastes. The world community mandate for engines that are clean, quiet, durable and fuel efficient will be satisfied, increasingly, by first-tier component suppliers developing integrated systems solutions.
Many areas of the world are in various stages of development which frequently includes a rapid increase in the motor vehicle population. As a result, some areas are beginning to show the effect of increased motor vehicle use on air pollution. The vehicle's contribution to California's air pollution has long been recognized and studied, and measures have been implemented to reduce emissions from motor vehicles. The history of light duty vehicle emission control in the South Coast Air Basin of California is reviewed. Emission reductions achieved, current levels, projected future emissions and the need for further emissions reductions from light duty vehicles are discussed. For other areas of the world where motor vehicles contribute to air pollution, suggestions are made which can improve the effectiveness of emission control efforts; which should be consistent with political and economic realities, and efforts to achieve international harmonization of standards.
Transfer Path Analysis (TPA) is a widely used methodology in Noise, Vibration and Harshness (NVH) analysis of motor vehicles. Either it is used to design a vehicle from scratch or it is applied to root cause an existing NVH problem, TPA can be a useful tool. TPA analysis is closely related to the concept of partial contribution. The very basic assumption in TPA is that the summation of all partial contributions from different paths constitutes the total response (which could be either tactile or acoustic). Another popular concept in NVH analysis of vehicles is the component sensitivity. Component sensitivity is a measure of how much the response changes due to a change in one of the components of the system, i.e., the thickness of a panel or elastic rate of an engine mount. Sensitivity rates are more popular among CAE/Simulation community, simply because they are reasonably easy to calculate using mathematical models.
An overview of model development for seated occupants is presented. Two approaches have been investigated for modeling the vertical response of a seated dummy: finite element and simplified mass-spring-damper methods. The construction and implementation of these models are described, and the various successes and drawbacks of each modeling approach are discussed. To evaluate the performance of the models, emphasis was also placed on producing accurate, repeatable measurements of the static and dynamic characteristics of a seated dummy.
Modern trends in noise control engineering have subjected the automobile to the “drained swamp” syndrome. Squeaks and rattles (S&R) have surfaced as major concerns. Customers increasingly perceive S&R as direct indicators of vehicle build quality and durability. The high profile nature of S&R has led manufacturers to formulate numerous specifications for assemblies and components. Even so, a large majority of buzz, squeak and rattle (BSR) issues are identified very late in the production cycle, some often after the vehicle is launched. Traditionally, the “find-and-fix” approach is widely adopted, leading to extensive BSR warranty bills. The “design-right-the-first-time” approach must replace the “find-and-fix” approach. Due to the vast breadth and depth of S&R issues, a comprehensive summary of the present state of the art is essential. This paper includes a literature survey of the current state of the art of S&R, and discusses the methods available to further advance it.
This paper describes the procedures used to reduce the tonal noise of a class eight truck engine timing gear train that was initially found to be objectionable under idle operating conditions. Initial measurements showed that the objectionable sounds were related to the fundamental gear mesh frequency, and its second and third harmonics. Experimental and computational procedures used to study and trouble-shoot the problem include vibration and sound measurements, transmission error analysis of the gears under light load condition, and a dynamic analysis of the drive system. Detail applications of these techniques are described in this paper.
A design framework based on the principles of lean manufacturing and axiomatic design was used as a guideline for designing an automotive component manufacturing system. A brief overview of this design decomposition is given to review its structure and usefulness. Examples are examined to demonstrate how this design framework was applied to the design of a gear manufacturing system. These examples demonstrate the impact that low-level design decisions can have on high-level system objectives and the need for a systems-thinking approach in manufacturing system design. Results are presented to show the estimated performance improvements resulting from the new system design.
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.
This paper provides twelve rules to help reduce four key ergonomic risk factors (force, frequency, posture and mechanical stress). These rules were developed to assist individuals who may not have received extensive ergonomic training but who are involved in implementing any changes (major or minor) to manufacturing work stations. This includes changes in task and/or changes in equipment. A complete ergonomic analysis of a work situation is a good idea in most cases, but these rules will avoid many of the commonly occurring problems if applied early in the design or modification of a workplace.
This paper discusses the evolution of graduate education in manufacturing engineering and the curriculum needed to educate manufacturing engineers in the automotive industry. This paper examines the master's and doctoral curriculum in manufacturing engineering at the University of Michigan-Dearborn. Finally, it proposes future direction for graduate education in manufacturing that will be needed for the automotive industry of the future.
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.