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OEM and Tier One integrated suppliers are in constant search of cockpit system components that reduce the overall number of breaks across smooth surfaces. Traditionally, soft instrument panels with seamless airbag systems have required a separate airbag door and a tether or steel hinge mechanism to secure the door during a deployment. In addition, a scoring operation is necessary to ensure predictable, repeatable deployment characteristics. The purpose of this paper is to demonstrate the development and performance of a cost-effective soft instrument panel with a seamless airbag door that results in a reduced number of parts and a highly efficient manufacturing process. Because of the unique characteristics of this material, a cost-effective, lightweight solution to meet both styling requirements, as well as safety and performance criteria, can be attained.

The automotive industry is continually striving for opportunities to take additional cost and mass out of vehicle systems. Large parts such as an Instrument Panel retainer are good candidates because a small percent reduction in mass can translate into a significant material mass savings. Multiple requirements for a soft instrument panel including safety, stiffness, adhesion, etc. can make these savings difficult to achieve. This paper will describe how a new material and process development for the fabrication of a soft instrument panel can produce 50% weight savings with a 20% cost reduction potential. In addition, this new technology exhibits improved performance over existing materials during safety testing.

This paper will discuss, compare, and contrast current materials, designs, and manufacturing options for fuel filler doors. Also, it will explore the advantages of using conductive thermoplastic substrates over other materials that are commonly used in the fuel filler door market today. At the outset, the paper will discuss the differences between traditional steel fuel filler doors, which use an on-line painting process, and fuel filler doors that use a conductive thermoplastic substrate and require an in-line or off-line painting process. After reviewing the process, this paper will discuss material options and current technology. Here, we will highlight key drivers to thermoplastics acceptance, and look at the cost saving opportunities presented by the inline paint process option using a conductive thermoplastic resin, as well as benefits gained in quality control, component storage and coordination.

The history behind Polymer Class “A” Body Panels for automotive applications is very interesting. The driving factors behind these applications have not changed significantly over the past sixty years. Foremost among these factors is the need for corrosion and dent resistance. Beginning with Saturn in 1990, interest in polymer body panels grew and continues to grow up to the present day, with every new global application. Today, consumers and economic factors drive the industry trend towards plastic body panels. These include increased customization and fuel economy on the consumer side. Economic factors such as lower unit build quantities, reduced vehicle mass, investment cost, and tooling lead times influence material choice for industry. The highest possible performance, and fuel economy, at the lowest price have always been a goal.

Automotive interiors are undergoing rapid transformation with the introduction of invisible PSIR integral systems. This styling trend requires continuous class A surface for the Instrument Panel (IP) and introduces complexities in the design and analysis of PSIR integral systems. The most important criterion for airbag doors is that it must open as intended, at the tearseam, within the deployment temperature range and without fragmentation. Consequently it is imperative that in analytical simulations, the finite element model of the tearseam is accurate. The accuracy of the model is governed by (a) optimal level of refinement, (b) surface geometry representation and (c) material model. This paper discusses modeling methodology for tearseams with respect to mesh refinement and the effect of geometry.

As the global auto industry wrote the final chapter on its first century, we saw the average thickness of an automotive instrument panel drop from 3.0 mm-3.5 mm to 2.0 mm-2.3 mm, as found in the 1999 Volkswagen Jetta and Golf. By reducing the wall thickness of the instrument panel, Volkswagen started an industry trend: both OEMs and tiers are investigating technologies to produce parts that combine a lower cost-per-part via material optimization and cycle-time reduction with the superior performance of engineering thermoplastics. The goal is to produce parts that are positioned more competitively at every stage of the development cycle - from design, to manufacturing, to assembly, to “curb appeal” on the showroom floor. The key to this manufacturing and design “sweet spot” is a technology called thinwall - the molding of plastic parts from engineering thermoplastics with wall thicknesses thinner than conventional parts of similar geometry.

As the need for plastic components with high-performance and low systems cost continues to escalate, the issues associated with bringing applications to automotive market have become more complex. Automotive applications such as seamless integral Passive Supplemental Inflatable Restraint (PSIR) systems can have tearseams that are either molded-in or laser scored. Molded-in tearseams in seamless Instrument Panels (IP) eliminate the secondary operation of laser scoring, but they warrant thin wall molding conditions. This paper describes material characterization under thinwall molding conditions wherein the effects of processing on mechanical properties are explored. This paper also discusses results from a proprietary finite element code developed at GE to predict the processing parameters, which affect the mechanical properties of the material at the tearseam in a seamless IP system.

The thermal performance of an automotive forward-lighting assembly is predicted with a computational fluid-dynamics (CFD) program. A three-dimensional, steady-state heat-transfer model seeks to account for convection and radiation within the enclosure, conduction through the thermoplastic walls and lens, and external convection and radiation losses. The predicted temperatures agree well with experimental thermocouple and infrared data on the housing. Driven by the thermal expansion of the air near the bulb surface, counter-rotating recirculation zones are predicted within the enclosure. The highest temperatures in the plastic components are predicted on the inner surface of the shelf above the bulb where airflow rising from the hot bulb surface impinges.

Textron Automotive Trim, Valeo Climate Control, and Torrington Research Company, with assistance from GE Plastics, have developed an integrated instrument panel system to meet ever-increasing industry targets for: Investment and piece-cost reduction; Mass/weight savings; Quality and performance improvements; Packaging and space availability; Government regulation levels; and Innovative technology. This system, developed through feedback with the DaimlerChrysler Corporation, combines the distinctive requirements of the instrument panel (IP) with the heater-ventilation-air-conditioning (HVAC) assembly. Implementing development disciplines such as benchmarking, brainstorming, and force ranking, a number of concepts were generated and evaluated. Using a current-production, small, multi-purpose vehicle environment, a mainstream concept was designed and engineered.

Using a combination of engineering test experience, explicit finite-element analysis, and advanced materials characterization, a predictive engineering method has been developed that can assist in the development of active top pads. An active top pad is the component of the instrument panel that covers the passenger airbag module and articulates during a crash event, allowing the airbag to deploy. This paper highlights the predictive analysis method, analytical results interpretation, and suggestions for future development.

With parts consolidation and increasing systems performance requirements, instrument panel systems have become increasingly complex. For these systems, the use of predictive engineering tools can often reduce development time and cost. This paper outlines the use of such tools to support the design and development of an instrument panel (IP) system. Full-scale test results (NVH, head impact, etc.) of this recently introduced IP system were compared with predicted values. Additionally, results from moldfilling analysis and manufacturing simulation are also provided.

Automotive styling trends point to reduced bumper overhang, greater sweeps, and reduced overall package space for the bumper system. At the same time engineers are charged with improving bumper performance to reduce collision repair costs and enhance occupant safety further. Two key performance parameters for the bumper to meet these conflicting objectives are fast but controlled loading and efficient energy absorption (EA). The majority of today's North American passenger-car bumper systems consist of a reinforcing bar either of steel, aluminum, or composite construction, and an energy absorption media. The most widely used energy-absorber construction is made from an expanded-polypropylene foam (EPP). Honeycomb energy absorbers, which are made from an ethylene vinyl acetate (EVA) copolymer, are also still used on some of today's cars. This paper will address an alternative to the bumper energy absorber systems described above.

Use of thermoplastic materials for throttle body applications can offer substantial weight, cost, and integration benefits. This paper will discuss the many elements that comprise materials selection, as well as the design and testing of composite throttle bodies. Polyetherimide (PEI), polyphenylene sulfide (PPS), and polybutylene terephthalate (PBT) materials will be discussed and compared as candidates for automotive throttle bodies. The focus areas that will be covered in this paper include: Materials Selection - The criteria for materials selection will be discussed and the properties of candidate thermoplastics compared with key requirements of throttle body applications. Bore and Plate Dimensional Stability and Consistency - The effects of thermal cycling, coefficient of thermal expansion, humidity, and design will be discussed, as well as their relation to bore/plate air leakage.

The instrument panel (IP) is one of the largest, most complex, and visible components of the vehicle interior, and like most other major systems in passenger cars and light trucks, it has undergone considerable aesthetic and functional changes over the past decade. This is because a number of design, engineering, and manufacturing trends have been driving modifications in both the role of these systems and the materials used to construct them since the mid- '80s. This paper will trace the recent evolution of IP systems in terms of the trends affecting both design and materials usage. Specific commercial examples will be used to illustrate these changes.

Designers and engineers encounter many challenges in developing vehicles for the small-car market. They face constant pressure to reduce both mass and cost while still producing vehicles that meet environmental and safety requirements. At the same time, today's discriminating consumers demand the highest quality in their vehicles. To accommodate these challenges, OEMs and suppliers are working together to improve all components and systems for the high-volume small-car market. An example of this cooperative effort is a project involving an integrated structural instrument panel (IP) designed to meet the specific needs of the small-car platform. Preliminary validation of the IP project, which uses a compression-molded, glass-mat-thermoplastic (GMT) composite and incorporates steel and magnesium, indicates it will significantly reduce part count, mass, assembly time, and overall cost.

Traditional knee bolster designs consist of a first-surface plastic component covered by paint or vinyl skin and foam, with a subsurface steel plate that transfers knee loads to 2 steel crush brackets. The design was developed to meet FMVSS 208 and OEM requirements. More recently, technological developments have allowed for the steel plate to be replaced by a ribbed plastic structure, which offers cost and weight savings to the instrument panel system. However, it is still a hybrid system that combines plastic with the 2 steel crush brackets. This paper will detail the development of an all-plastic design, which consolidates the plastic ribbed reinforcement plate with the 2 steel crush cans in a single engineering thermoplastic component. The new system is expected to offer further cost and weight savings.

As automakers struggle to meet often conflicting safety, weight, styling, and performance requirements, engineering thermoplastics (ETPs) are making increasing inroads into applications that once were the exclusive domain of metals, glass, and thermosets. A good example of this is in the door systems area, where the performance, design flexibility, aesthetics, parts integration, and lower specific gravity offered by ETPs are allowing highly integrated and efficient modules to be created that, in turn, increase assembly efficiency and reduce mass, part count, warranty issues, and systems costs. This paper will use several case studies on innovative door hardware modules and door panels to illustrate the advantages offered by this versatile class of engineering materials.