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Simplified mathematical modeling has been employed to investigate the relationship between automobile forestructure energy absorption and the restraint loads applied to passengers during a 30 mph barrier collision. A two-massmodel was developed and validated to compute restraint loading from a given passenger compartment deceleration. The effect of various deceleration curves, representing forestructure modifications, is reported. A “constant force” restraint system is also evaluated.

A unique opportunity arose to make a direct comparison of aluminum, sheet molding compound (SMC) and steel using a common hood design. In considering all possible material combinations of inner and outer panels, it was discovered that some of the combinations were incompatible due to material properties. Only the compatible material combinations were considered. Three different joining techniques - welding, bonding and bonded hem flanging - were evaluated. The cost, weight and structural performance of the chosen hood material combinations were established. Areas of further development were identified, including design optimization for specific material combinations.

Present techniques for classification and analysis of surface roughness are based on a trace of surface profile, or a measure of arithmetic mean, or rms value of the profile height, but this information is not adequate, and a new technique has been developed to classify surface roughness based on frequency content of the variance of the surface profile. A digital computer frequency filter has been devised to allow differentiation between roughness height and waviness or general surface contour. Three representative surfaces have been measured and classified according to this analysis and data are presented in support for roughness classification techniques.

Starting in 1965 and continuing through 1972, the Radio Committee of the Motor Vehicles Manufacturers Association (MVMA) has been the coordinator of a number of electromagnetic research projects. These investigations have included extensive applications of the updated SAE Standard, Measurement of Electromagnetic Radiation From Motor Vehicles (20-1000 MHz)-SAE J551a. Furthermore, there were joint testing programs with the Electronic Industries Association which encompassed measuring degradation in the performance of Land Mobile Radio Service receivers resulting from varying levels of impulsive-type radiation from motor vehicles. In addition, efforts were expended in using statistical approaches for testing a number of hypotheses covering a conversion of impulsive vehicle noise data to the interference potential to Land Mobile receivers.

Resistance to dents and dings, caused by plant handling and in-service use, is generally recognized as an important performance requirement for automotive outer body panels. This paper examines the dent resistance improvements that can be achieved by maximizing surface stretch, through adjustments to the press settings, and substitution of a higher strength steel grade. Initially, the stamping process was optimized using the steel supplied for production: a Ti/Nb-stabilized, ultra low carbon (ULC) grade. The stamping process was subsequently optimized with a Nb-stabilized, rephosphorized ULC steel, at various thicknesses. The formed panels were evaluated for percent surface stretch, percent thinning, in-panel yield strength after forming, and dent performance. The results showed that dent resistance can be significantly improved, even at a reduced steel thickness, thus demonstrating a potential for weight savings.

The commercial validation of a optimized RRIM polyurethane substrate with a novel barrier coat for fascia applications is reviewed which creates cost competitiveness to thermoplastic olefins (TPO), without sacrificing performance. Meeting fascia performance requirements with thinner and lighter RRIM materials containing recyclate and the subsequent application of a barrier coat eliminating the traditional primecoat cycle was investigated.

This paper directs attention to a specific region of the air-bag deployment process. Both experimental and analytical results are presented. Experimental procedures and their results are presented along with a two dimensional unsteady isentropic CFD model and a empirical gas-jet model.

A better understanding of turbulent kinetic energy is important for improvement of fuel-air mixing, which can lead to lower emissions and reduced fuel consumption. An in-cylinder flow study was conducted using 1548 Laser Doppler Velocimetry (LDV) measurements inside one cylinder of a 3.5L four-valve engine. The measurement method, which simultaneously collects three-dimensional velocity data through a quartz cylinder, allowed a volumetric evaluation of turbulent kinetic energy (TKE) inside an automotive engine. The results were animated on a UNIX workstation, using a 3D wireframe model. The data visualization software allowed the computation of TKE isosurfaces, and identified regions of higher turbulence within the cylinder. The mean velocity fields created complex flow patterns with symmetries about the center plane between the two intake valves. High levels of TKE were found in regions of high shear flow, attributed to the collisions of intake flows.

This paper describes techniques that predict and analyze dynamic response of vehicles traversing random rough surfaces. Road irregularities are statistically classified by frequency and amplitude distribution. This classification determines the nature of random inputs to mathematical vehicle models and allows computer prediction of dynamic response of a simulated vehicle. Once inputs and models are defined, parametric analysis with output criteria specified statistically can be performed. This allows prediction of vehicle riding quality and evaluation of design concepts. Statistical analysis of accelerometer measurements on actual vehicles permits verification of the design process and meaningful comparison between vehicles.

Gasoline direct injection technology is receiving increased attention among automotive engineers due to its high potential to reach future emission and fuel economy goals. This paper reports some of the design and development techniques in use at Chrysler as applied to four-stroke Direct Injection Spark Ignition (DISI) engines. The spray characteristics of Chrysler's single-fluid high-pressure injector are reported. Tools used in the design process are identified. Observations of the in-cylinder fuel/air mixing process using laser diagnostic techniques and Computational Fluid Dynamics (CFD) are described. Finally, combustion and emissions characteristics using Design of Experiment (DoE) tests are presented.

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.

This paper describes the application of the Design for Manufacture and Assembly (DFMA) method at Chrysler. Attention is focused on the development of the clutch and brake pedal and bracketry system of the PL project in the Small Car Platform. The Chrysler DFMA procedure including competitive evaluation and value engineering was utilized during the initial design phase involving product concept development from the original functional and manufacturing requirements. After the first laboratory tests, a number of key design and manufacturing concerns surfaced and led to a second cycle of DFMA analysis. The procedure permits major design functions and manufacturing and assembly process issues and criteria to be incorporated in the initial design stages.

Computer-aided engineering (CAE) is generally recognized as an important method of improving productivity. One of the major benefits of this technology has been to reduce the amount of manual labor spent analyzing changes made to vehicle designs. By using existing data, computer-aided design (CAD) can be used to co-ordinate the spatial relationships of the driver, passengers, engines, suspensions, tires, driver controls, and other body and chassis components. Special files containing a specific set of user-defined CAD language instructions, referred to as macros, are discussed and illustrated. Also included are tire clearance studies and master reference vehicle dimension files.

A new 10 cell engine dynamometer complex, (Fig. 1) which provides optimized testing and development capacity for new lines of automotive power plants for the 1980's and beyond, has been built at Chrysler's Engineering Center. This modern facility combines “state of-the art” instrumentation for control, data gathering, and data analysis with new operating concepts which together allow for high levels of accuracy, repeatability, and productivity previously not attainable in the area of engine testing and development.

Using an evolutionary design process, Chrysler has developed a multi-purpose fuel injection controller which goes well beyond simply delivering fuel. Designed with efficiency in mind, this microprocessor based system brings sophisticated technology to the automobile in a reliable and serviceable form.

In anticipation of complying with European standards for impact protection, an instrument panel design was analyzed to determine A. impact zone boundaries B. impact test velocitiesfor the head of a front seat passenger. Chrysler computer aided design (C.A.D.) surfacing capabilities were utilized in the solution. Early knowledge of impact zone location is important to intelligent design decisions; knowledge of impact velocities aids in performing compliance testing.

The basic theory and the techniques upon which the Air Conditioning Analytical Simulation Package (A/CASP) computer program system was developed is outlined. Methods for simulating car air conditioning components, systems, and cool-down performance by computerized mathematical models are presented. Solution techniques for the models of the evaporator, condenser, compressor, and vehicle are outlined. The correlation of test data and analytical predictions is demonstrated.

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.

Basic procedures are described for the design and development of flexible drive plates that couple automatic transmissions to engines. An innovative combination of analysis and test techniques were employed during the development of a drive plate for a turbocharged diesel truck engine when premature failures occurred. FEA (finite element analysis) was expanded from use as a preliminary design tool to the prediction of high stress conditions and the loading that caused them. A laboratory test was developed to rapidly assess drive plate design changes based on these FEA predictions.

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.