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This study analyzes the vibration characteristics of the valve train of a 2.0L SOHC Chrysler Corp. Neon engine over a range of operating speeds to investigate and demonstrate the advantages and limitations of various dynamic measurements such as displacement, velocity, and acceleration in this application. The valve train was tested in a motoring fixture at speeds of 500 to 3500 camshaft rpm. The advantages of analyzing both time and frequency domain measurements are described. Both frequency and order analysis were done on the data. The theoretical order spectra of cam displacement and acceleration were computed and compared to the experimental data. Deconvolution was used to uncover characteristic frequencies of vibration in the system. The theoretical cam acceleration spectrum was deconvolved from measured acceleration spectra to reveal the frequency response function of the follower system.

To understand how the passenger compartment cavity interacts with the surrounding panels (roof, windshield, dash panel, etc) a numerical panel contribution analysis was performed using FEA and BEA techniques. An experimental panel contribution analysis was conducted by Reiter Automotive Systems. Test results showed good correlation with the simulation results. After gaining some insight into panel contributions for power train noise, an attempt was made to introduce beads in panels to reduce vibration levels. A fully trimmed body structural-acoustic FEA model was used in this analysis. A network of massless beam elements was created in the model. This full structural-acoustic FEA model was then used to determine the optimal location for the beads, using the added beams as optimization variables.

Hand dismantling of certain automotive parts has been an accepted process to remove high value materials, but in large scale recycling this may not be economical. In plastics, a pure non contaminated material stream is critical for maintaining high material values and this means designing plastic parts that can be machine separated. One candidate for separating the plastics in vehicle subsystems such as instrument panels and door trim panels is density separation. In order to better understand what processes are required to develop design requirements for automated plastic separation methods Chrysler and the Vehicle Recycling Partnership have undertaken a major materials separation study with MBA Polymers. In this paper, we describe the material separation methods and the application of these methods to three automotive interior assemblies.

Environmental costs are a delayed financial burden that result from product decisions made early in the product life cycle--early material choices may create regulatory and waste management costs that were not factored into the acquisition cost. This paper outlines a step-wise approach to determine decision points; environmental, health, safety and recycling (EHS&R) cost drivers that affect decisions; and sources of information required to conduct a Life Cycle Management (LCM) review. Additionally, how LCM fits into the larger concurrent engineering framework is illustrated with an electrocoat primer example. Upstream and downstream supply chain processes are reviewed, as well as organizational challenges that affect the decision process.

Energy management materials are widely used in automotive interiors in instrument panel, knee bolster, and door absorber applications to reduce the risk of injury to an occupant during a crash. Automobile manufacturers must meet standards set by the National Highway Traffic Safety Administration (NHTSA) that identify maximum levels of injury to an occupant. The recent NHTSA upgrade to the Federal Motor Vehicle Safety Standard (FMVSS) 201 test procedure(1) for upper interior head impact protection has prompted energy management materials' use in several new areas of affected vehicles. While vehicle evaluations continue, results to date show that energy management foams can be effective in reducing the head injury criterion [HIC(d)] to acceptable government and OEM levels.

Due to new regulations, emissions development and compliance testing have become more complex. The amount of data acquired, the number of test types, and the variety of test conditions have increased greatly. Due to this increase, managing test information from request to analysis of results has become a critical factor. Also, automated test result presentation and test storage increases the value and quality of each test. This paper describes a computer system developed to cope with the increasing complexity of vehicle emission testing.

Testing for vehicle emissions and fuel economy certification occurs primarily on chassis dynamometers in a laboratory setting and therefore the actual road conditions, such as forces due to tire rolling resistance and internal friction, must be simulated. Test track coastdown procedures measure vehicle road load forces and produce an equation which relates these forces to velocity. The recent inclusion of onboard anemometry has allowed the coastdown procedure to account for varying wind effects; however, the new anemometer based mechanical loss coefficients do not take into account ambient weather conditions. The two purposes of this study are (1) to determine the new tire rolling resistance temperature correction coefficient that should be used when test ambient temperature is different from the standard reference value of 68°F, and (2) to investigate the effects of auxiliary measurements, such as other ambient conditions and vehicle settings, on this correction coefficient.

This paper outlines several methodologies which use finite element and experimental models to predict vehicle NVH responses. Trimmed body experimental modal subsystem models are incorporated into the finite element system model to evaluate engine mounting systems for low frequency vibration problems. Higher frequency noise issues related to road input are evaluated using experimentally derived acoustic transfer functions combined with finite element subsystem model responses. Specific examples of system models built to simulate idle shake and road noise are given. Applications to engine mounting, suspension design, and body structure criteria are discussed.

The low noise and linear sound level characteristics of passenger vehicles are receiving increased scrutiny from automotive journalists. A linear noise level rise with increasing engine rpm is the first basic aspect of insuring an acceptable vehicle interior engine noise sound quality. In a typical case of structural response to engine vibration input, interior noise begins to rise with rpm, remains constant or even drops as the engine continues to accelerate, and then exhibits a noise period corresponding to the structure's natural frequency. Frequently this nonlinearity is bothersome to the customer. During the development process, Chrysler's Dodge and Plymouth Neon exhibited just such a nonlinear rise in noise level, heard within the passenger compartment, when the vehicle was accelerated through 4200 rpm.

A mathematical model was developed to evaluate design options for control of road noise transmission into the interior of a passenger car. Both air-borne and structure-borne road noise over the frequency range of 200-5000 Hz was able to be considered using the Statistical Energy Analysis (SEA) method. Acoustic and vibration measurements conducted on a laboratory rolling road were used to represent the tire noise “source” functions. The SEA model was correlated to in car sound pressure level measurements to within 2-4 db accuracy, and showed that airborne noise dominated structure-borne noise sources above 400 Hz. The effectiveness of different noise control treatments was simulated and in some cases evaluated with tests.

The J1850 bus requirements promote an unique and well characterized physical layer behavior developed through the learning curve of previous multiplex solutions. Design requirements such as: 1) Reliably interconnecting all of the vehicle's most complex modules, 2) Consistently withstanding the vehicle's harsh environment, and 3) Meeting SAE's functionality requirements, were all a formidable task to achieve. This paper will highlight the path taken to achieve a J1850 Bus interface which successfully met all of the design and functional goals. Chrysler's C2D insights will be discussed and related to goals for J1850. Other design considerations will also be discussed such as EMC issues, custom test equipment, and vehicle and component testability. In turn, silicon processes with special structures and topologies will be discussed relating the specific design with the needed electrical behavior. The HIP7020 J1850 BUS TRANSCEIVER I/O for MULTIPLEX WIRING accomplishes these requirements.

MIL 3's OPNET simulator was used to model Chrysler's J1850 bus. Modeled were both J1850 bus characteristics and those portions of control modules (e.g., the engine controller) which communicate on the bus. Current Chrysler control module algorithms and proposed Chrysler J1850 message formats were used to design the control module models. The control module models include all messages which are transmitted at fixed intervals over the J1850 bus. The effects of function-based messages (e.g., messages to be transmitted on a particular sensor or push-button reading) on system load were investigated by transmitting an additional message with a fixed, relatively high priority at 50 millisecond intervals.

Vacuum insulation and phase-change thermal storage have been used to enhance the heat retention of a prototype catalytic converter. Storing heat in the converter between trips allows exhaust gases to be converted more quickly, significantly reducing cold-start emissions. Using a small metal hydride, the thermal conductance of the vacuum insulation can be varied continuously between 0.49 and 27 W/m2K (R-12 to R-0.2 insulation) to prevent overheating of the catalyst. A prototype was installed in a Dodge Neon with a 2.0-liter engine. Following a standard preconditioning and a 23-hour cold soak, an FTP (Federal Test Procedure) emissions test was performed. Although exhaust temperatures during the preconditioning were not hot enough to melt the phase-change material, the vacuum insulation performed well, resulting in a converter temperature of 146°C after the 23-hour cold soak at 27°C.

This paper describes the development of a rubber-like skin Finite Elements Model (FEM) for the Hybrid III headform and an experimental method to determine its material properties. The finite element modeling procedures, using material parameters derived from tests conducted on the headform skin (rubber) material, are described. Dynamic responses and computations of HIC using the developed headform model show that an Elastic-Plastic Hydrodynamic (EPH) material model of the rubber can be used for headform impact simulations. The results obtained from the headform simulation using an EPH rubber material model and drop tower tests of the headform on both a rigid and a deformable structure will be compared, in order to show the applicability of the EPH model.

Voltage and current surges are a major concern when it comes to ensuring the functional integrity of electrical and electronic components and modules in an automobile system. This paper presents a computer simulation study for analyzing the effect of high voltage spikes and current load dump on a new Integrated Driver/Receiver (IDR) IC, currently being developed for a J1850 Data Communication Bus in an automobile. It describes the modeling and simulation of the protection structure proposed for the device. The simulation study yields a prediction of current and voltage capability of the protection circuit based on thermal breakdown and transient responses of the circuit. Two levels of modeling, namely, the behavioral level model and the component level model, are used to generate the simulation results. Experimental data will be acquired and used to validate the simulation model when the actual device becomes available.

The interaction ILLEGIBLEf the chest of the Hybrid III dummy with the air bag restrILLEGIBLEt system during a crash is complex. Forces applied to one ILLEGIBLEmponent of the dummy can generate an unexpected response in a distal part. Motion, both linear and angular, of the pelvis during impact can create an enigmatic spike in the acceleration of the chest. Because significant changes in the chest acceleration response can affect the development of an airbag system, this pelvis-chest interaction is cause for concern. The factors that appear to affect the chest acceleration spike as a result of the pelvis-chest interaction are: the mass moment of inertia of the pelvis, the interaction of the pelvis with the femur, the characteristic of the lumbar spine, and the differential velocity of the pelvis with respect to the chest.

The changes in reliability of the Electrical/Electronic Systems of a vehicle-line during its early design and development engineering processes have been studied. A computerized vehicle failure tracking system was used to provide results from several stages of early development vehicle testing at the proving grounds. The data were analyzed using a software program that assumes that failures in a repairable system, such as a car, occur as a nonhomogeneous Poisson process. Results suggest that, under normal circumstances, a significant and quantitative improvement in reliability is achievable as the system or component design progresses through the early design and development processes. This also provides a means of predicting future system(s) reliability when the system(s) is in production.

Federal legislation mandates that automotive OEMS provide occupant protection in collisions involving front and side impacts This legislation, which is to be phased-in over several years, covers not only passenger cars but also light-duty trucks and multipurpose passenger vehicles (MPVs) having a gross vehicle weigh rating (GVWR) of 8,500 lb (3,850 kg) or less. During a frontal impact, occupants within the vehicle undergo rapid changes in velocity. This is primarily due to rapid vehicle deceleration caused by the rigid nature of the vehicle's metal frame components and body assembly. Many of today's vehicles incorporate deformable, energy-absorbing (EA) structures within the vehicle structure to manage the collision energy and slow the deceleration which in turn can lower the occupant velocity relative to the vehicle. Occupant velocities can be higher in light-duty trucks and MPVs having a full-frame structure resulting in increased demands on the supplemental restraint system (SRS).

To evaluate and refine interior architecture of the new Dodge Ram pickup truck three years before production, a road worthy interior package validation buck was built using a fiberglass body shell. Molds for the shell were made using CAD/CAM techniques. Advanced CAD/CAM techniques were used to build the interior buck of a subsequent model from individual panels molded in carbon fiber. This buck also included inner structural panels and interior trim components taken from CAD data. For this and subsequent new vehicle programs, refinement of construction techniques allows the bucks to serve as aids in product design and manufacturing feasibility studies.

This paper presents the development of a test procedure for evaluation of inadvertent deployment of air bags. The methodology and early development of the procedure is discussed along with additional criteria thought to be required for trucks and sport utility vehicles. Tests conducted address severe off-road use in relation to air bag sensing systems. Data is collected from accelerometers. After worst case test conditions are identified (examples include rough road, snow plowing and jerk towing events), the data is analyzed and comparisons for design decisions can be made.