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An air-to-fuel ratio (A/F) modulation scheme is presented in which a linear feedback signal is generated from a heated exhaust gas oxygen (EGO) sensor. In this scheme, the engine A/F is modulated with a triangular waveform, and the mean value of the EGO output is obtained using a rolling average filter. The resulting output is linearly related to the exhaust A/F, and is used to provide closed-loop lean A/F operation following a cold start to enhance catalyst light-off and minimize vehicle exhaust emissions. Some engine-dynamometer results obtained using the method are presented.

The design of a canned ceramic oval converter, 77mm by 146.8mm, is described along with subsequent demonstration of its high temperature (1050°C) durability. A new mat deterioration phenomenon was recognized, and will be described. The mat deterioration results from sintering of the vermiculite and glass fiber structure when exposed to temperatures greater than approximately 1000°C. Due to the extremely high temperature experienced in the supporting mat of an oval converter exposed to 1050°C, an alternative mat configuration was utilized to eliminate potential mat sintering. An inner layer of non-intumescent mat (1500g/m2) was used in conjunction with an outer layer of intumescent mat (3100g/m2). The inner mat provided sufficient thermal protection to the outer intumescent mat, maintaining considerable holding pressure on the ceramic substrate. A tourniquet closure technique was developed to uniformly compress a hybrid mat system around the entire perimeter of the oval converter.

Textron Automotive has developed a new thermoplastic castable aliphatic urethane for an instrument panel with a seamless passenger side air bag on a 1998 North American vehicle. This material was developed to meet the increased temperature range demands for a top mount seamless or invisible passenger side air bag instrument panel. Traditional castable thermoplastic materials were developed to meet aesthetic requirements until the advent of passenger side air bags forced the instrument panel to become a functional component. Conventional coverstock materials cannot meet the -40°C and 120°C air bag deployment conditions that are proposed. This paper describes: the advantages of an invisible or seamless instrument panel; the new material performance requirements to meet the invisible PSIR requirements; the advantages of thermoplastic urethane (TPU) compared to current instrument panel materials.

The possibility of changes in field life requirements, elimination of PVC in Europe and the push for a totally recyclable instrument panel have been the driving factors in the automotive industry for the replacement of polyvinyl chloride, PVC with thermoplastic olefin, TPO for automotive interiors. Field life requirements for instrument panels for the North American market has risen to 10 years of desert exposure or equivalent sealed box solar exposure. The TPO developed by Delphi is one of only a few materials able to retain its physical properties and color after this harsh exposure. TPO is fully recyclable, it can be ground and re-extruded into sheet form or ground and reused as a part of an all olefin instrument panel, TPO cover stock, polypropylene foam and rigid polypropylene substrate.

Choosing the correct thermoplastic for an instrument panel application requires a thorough understanding of the environmental and performance conditions. In the case of a high speed event, such as an airbag deployment or a knee bolster intrusion, standard static tensile properties may not adequately define the material performance. The engineer needs to understand the materials sensitivity to high strain rate extremes. The subject of this paper is the enhancement of part performance through the testing and knowledge of material performance over a range of strain rates.

The manner in which instrument panels (IPs) are designed and manufactured has changed considerably over the past decade. Recent trends such as increased size and complexity and seamless airbag designs have put pressure on suppliers of engineering thermoplastics (ETP) to provide new formulations that offer improved mechanical properties for higher performance or thinner wall designs; opportunities to lower costs through components integration and reduced materials usage; and the potential for higher manufacturing productivity via faster cycle times. Materials suppliers have responded with a variety of new products, in many cases designed specifically for instrument panel applications. Several of these products are the subject of this paper and will be introduced in terms of the performance benefits they can provide to IP designers and manufacturers.

Nowadays the use of magnesium automotive engineering has become an essential way for weight reduction. The change from conventional materials, such as zinc alloys, to lighter weight materials, such as magnesium alloys, is realizable at commercially competitive rates. This requires lightweight solutions, optimized design and advanced manufacturing processes. The goal of this study is to validate the thixocasting process for a part of a wiper system. This paper summarizes the first mechanical tests carried out on a wiper part in AZ91 magnesium alloy by thixocasting and traditional casting process. The semi-solid die casting process enables to improve the mechanical behavior. To explain these results, the effects of microstructure on thermal properties are investigated and microstructural examination is also performed using optical microscope and scanning electronic microscope (SEM).

Thixomolding® produces net-shape parts from Magnesium alloys in a single step process involving high speed injection molding of semi-solid thixotropic alloys. A description of the process and status of commercial developments will be presented.. The mechanical properties and microstructures of Thixomolded® AZ-91D magnesium materials will be presented. Tensile strengths of semi-solid AZ-91D at both room temperature and elevated temperatures ( 373K, 423K) are compared with die cast AZ-91D. Data on enhanced creep properties of Thixomolded® AZ91-D alloy relative to die cast AZ-91D will be examined with respect to relative changes in microstructural features. Controlling the percent solids in the semi-solid state prior to injection molding can lead to improved creep performance for use in net-shape automotive components.

Mist generated from water-soluble fluids used in machining operations represents a potentially significant contribution to worker exposure to airborne particles. Part I of this study [1], discussed polymer additives as mist suppressants for straight mineral oil metalworking fluids (MWF), which have been successfully employed at several locations. This paper focuses on recent developments in polymer mist suppressants for water-based MWF, particularly in the production environment. The polymer developed and tested in this study functions on a similar basis to that for straight oil anti-mist additives. This water soluble polymer suppresses the formation of small mist droplets and results in a distribution of larger droplet sizes. These larger droplets tend to settle out near the point of machining, resulting in a significant decrease in the total airborne mist concentration.

New magnesium alloys based on Mg-Zn-Al-Ca quaternary system (ZAC alloys) have been developed by IMRA America, Inc. The 200-hour creep extension of the new ZAC alloys at 150°C and 35MPa is approximately one order of magnitude less than that of conventional Mg-Al based die cast alloy AZ91D, and is also slightly lower than that of aluminum die casting alloy A380. The tensile and corrosion properties of the new alloys are slightly better than, or comparable to, those of AZ91D alloy. It is generally known that the die-castability of Ca-containing magnesium alloys is relatively poor due to the hot-cracking and die-sticking problems associated with the calcium additions. However, this problem has been resolved in ZAC alloys where the high zinc content (∼8%) can restore the die-castability. The present paper summarizes the alloy design, microstructure, die casting process, mechanical and corrosion properties of the new ZAC alloys.

The anodization of aluminum is well established worldwide with many plants offering a range of production techniques suiting the requirements of a range of markets. Magnesium, while anodization processes have been known for some time, is poorly understood and little research has been done. Most processes have major drawbacks and attempts to replicate the finishes available for aluminum generally have not been successful. This paper sought to establish some fundamental reaction mechanisms and kinetics for the anodization of magnesium in commonly used electrolytes.

Several lead-free alloys have been studied for potential use in electronics by the National Center for Manufacturing Sciences(NCMS) Lead Free Solder Consortium that ended in 1996. Since then, one of these alloys has been studied using an existing product in order to determine the viability of Lead Free Vehicle Electronics. Design, supply chain, manufacturability, and reliability data for the electronics components and system are a part of this paper.

In the evaluation of plastic components during vehicle development, a relatively large number of items are evaluated as rejectable due to heat deformation. To reduce the vehicle development lead time, it would be desirable to establish an analytical technology using CAE to forecast vehicle performance with high order prediction. In the current study, the authors used “ABAQUS”, a superior tool for non-linear structural analysis, to conduct an FEM analysis considering thermal dependency, creep characteristics, and oval(escape heat stress) hole structure for mounting components. The analytical results confirmed the usefulness of the resin bumper numerical solution of thermal displacement. This report describes these results.

Recent vehicle design trends require bumper systems to be crashworthy under more demanding circumstances, e.g. tighter package space, heavier vehicle mass, and wider rail spans. Meanwhile, pressure to reduce cost and weight of bumpers continues at a time when roles in the supplier community are changing. These factors have combined to increase the importance of optimizing bumper design and material properties for specific platforms. Materials suppliers have responded by developing a range of specialized engineering thermoplastic (ETP) resins that can help meet increasing performance requirements yet also offer the potential for improved manufacturing productivity, significant weight savings, and systems cost reductions. Material suppliers have also increased the level of technical design support provided to OEMs and 1st Tier suppliers.

The approach of Life-Cycle Engineering (LCE) investigates technical, environmental and economical aspects of products and technologies to analyze weak points and optimization potentials as well as to support product and technology development. The use and the possibilities of LCE will be demonstrated with the example of three-way catalyst systems.

A calculation method of searching of optimum elastomer bumper shape is presented. The optimization criteria connected with static response curve are chosen. The optimization is carried out using polynomial approximation of an aid criterion and functional restrictions basing on calculations in specially chosen points of the acceptable values area. An algorithm of these calculations is developed. It is based on the finite element method taking into consideration unique elastomers characteristics such as ability to have big deformations without any failure and practical incompressibility. The loading is concerned as a sequence of some steps. Within of them the deformation increment is considered as small one. Such approach allows to analyse deformations as high as 50%. The corresponding software has been developed. The proposed approach and software can be used as some part of CAD/CAM system or as a separate tool of design of elastomer bumper systems.

A near-net forming process, FORMCAST™, has been developed with the capability of forming components from ductile metals into complex three dimensional shapes. Excellent as-formed mechanical properties are achieved as the material is under constant, high pressure during the forming process generating significant levels of work hardening. FORMCAST™ shares characteristics with other conventional processes (i.e., forming, casting, and extrusion), yet eliminates porosity, the need for draft angles, non-uniform material properties, excessive scrap, and shrinkage concerns. This paper will supply information to allow the comparison of FORMCAST™ to other processes. Items discussed will include the mechanics of the forming process, materials and that can be formed, as-formed material properties, characteristics, dimensional capabilities, and the process economics.

Olefin foam laminates are an interesting and cost-effective new materials option that can enhance design flexibility as well as improve manufacturing efficiencies and durability of padded interior-trim components, such as instrument panels and door-trim panels, headliners, seat backs, package shelves, and consoles, etc. In order to better understand the contributions of skin and foam material properties to the overall physical properties of the laminate, a study was undertaken at Visteon, an enterprise of Ford Motor Company. To prepare for testing, a number of different skin/foam laminate combinations were produced. The laminates were formed from 0.6-mm-thick PVC skins and foams from 2 different olefin families - a family specifically formulated for low-pressure molding operations and a family specifically formulated for vacuum forming. Within each family of materials, a matrix of 3 different foam thickness and 3 different foam density combinations were represented.

This paper presents an object-oriented method customized for a tool-assisted development of car software components. Tough market conditions motivate smart software development. ASCET SD is a tool to generate target code from graphic specifications, avoiding costly programming in C. But ASCET lacks guidelines on what to do, how to do it, in what order, like a fully equipped kitchen without a cooking book. Plans to employ the tool for BMW vehicle software sparked off demand for an adequate, object-oriented real-time methodology. We show how to scan the methodology market in order to adopt an already existing method for this purpose. The result of the adaptation of a chosen method to ASCET SD is a pragmatic version of ROOM, which we call BROOM. We present a modeling guidebook that includes process recommendations not only for the automotive sector, but for real-time software development in general.

The drive to reduce costs and increase efficiency in the automotive industry is often the driving force for development of new technologies and methods of engineering. Polypropylene (PP) is widely used as a low cost alternative to “engineering” thermoplastics. This paper outlines the characterisation methods used to develop material models for talc-filled impact-modified PP, which are then used to increase the efficiency of the development process, by using engineering analyses to reduce the prototyping costs and potentially the development time for an application. Instrument panels (IPs), door panels and trim parts are usually subjected to heat requirements and must maintain dimensional tolerance levels for each application. This necessitates extensive prototype testing and often several design iterations in order to reach the requirements. This paper deals with the characterisation of PP creep behaviour and development of a model for use in Finite-Element (FE) - based codes.