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COMPARISON of work capacity per unit mass and volume of different energy carriers shows that liquid hydrocarbons are superior to other energy sources. Solar and nuclear powerplants as well as their use in conjunction with a steam engine are examined in this paper. Suitability of an electric drive is discussed. Using a production 2-stroke diesel engine and its development forecast, a comparison is made of spark ignition, diesel, and gas turbine engines. The status of the free-piston engine turbine combination is reviewed.

AS a basis for the analyses of this symposium, a hypothetical car has been used to evaluate the engine power distribution in performance. Effects of fuel,-engine accessories, and certain car accessories are evaluated. The role of the transmission in making engine power useful at normal car speeds is also discussed. Variables encountered in wind and rolling resistance determinations are reevaluated by improved test techniques. Net horsepower of the car in terms of acceleration, passing ability and grade capability are also summarized.

Four multigrade engine oils, containing the same base oil plus SE additive package but VI improvers of differing shear stability, were evaluated in 80 000 km of high-speed, high-temperature vehicle service. Bearing, piston ring and valve guide wear, as well as oil consumption, oil filter plugging and engine cleanliness were all worse for the engines operated on the low-shear stability oils. The wear differences were traced to differences in high-shear-rate viscosity, while the cleanliness, filter plugging and oil consumption differences occurred because of excessive wear or polymer shear degradation. These results suggest that engine oil viscosity should be specified under high-shear-rate conditions.

A practical methodology is presented for the synthesis of Chassis Systems and their integration into a vehicle design to achieve a specified vehicle dynamic performance. By focusing on the fundamental performance requirements of gain, response time, and stability in midrange handling and the higher level design parameters of front and rear cornering compliance it is possible to find optimum values for these design parameters. The balancing of these higher level design parameters, in the context of overall vehicle performance, determines primary system requirements for the front suspension, rear suspension, tires, and steering system which may in turn be met by a variety of specific hardware designs.

Past studies have shown the applicability of advanced numerical methods for crashworthiness simulation. Lumped parameter (LP) modeling and finite element (FE) modeling have been demonstrated as two useful methodologies for achieving this endeavor. Experimental tests and analytical modeling using LP and FE techniques were performed on an experimental vehicle in order to evaluate the compatibility and interrelationship of the two numerical methods for crashworthiness simulation. The objective of the numerical analysis was to simulate the vehicle crashworthiness in a 0 degree, 48.6 KPH frontal impact. Additionally, a single commercial software, LS-DYNA3D, was used for both the LP and FE analysis.

The search for improvements in occupant protection under vehicle impact is hampered by a real lack of reliable biomechanical data. To help fill this void, General Motors has initiated joint research with independent researchers such as the School of Medicine, U. C. L. A. – in this case to study localized head and facial trauma — and has developed such unique laboratory tools as “Tramasaf,” a human-simulating headform, and “MetNet,” a pressure-sensitive metal foam. Research applied directly to product design also has culminated in developments such as the Side-Guard Beam for side impact protection.

THIS paper describes what the authors consider to be a simplified method of determining the vapor-locking tendencies of gasolines. The study of vapor lock was undertaken after they found the Reid vapor pressure method to be inadequate. The result of their work was the development of the General Motors vapor pressure, a single number which predicts vapor-locking tendency. The authors point out the following advantages of the new method: It allows direct comparisons of vapor-lock test results of different reference fuel systems; establishes distribution curves of volatility requirements of cars for vapor-lock free operation and of vapor-locking tendencies of gasolines; is a common reference value for both petroleum and automotive engineers. Finally, it more realistically evaluates the effects of small weathering losses on vapor-locking tendency than does Rvp.

The development of systems and components for control of exterior noise has traditionally been done through an iterative process of on road testing. Frequently, road testing of vehicle modifications are delayed due to ambient environmental changes that prevent testing. Vehicle dynamometers used for powertrain development often had limited space preventing far field measurements. Recently, several European vehicle manufacturers constructed facilities that provided adequate space for simulation of the road test. This paper describes the first implementation of that technology in the U.S.. The facility is typical of those used world wide, but it is important to recognize some of the challenges to effective utilization of the technique to correlate this measurement to on road certification.

Historically, the long development time required to produce a new automobile has meant that the electronics in that vehicle might lag the state-of-the-art by several years. For traditional vehicle electronics, this was certainly an appropriate delay, ensuring through extensive testing and qualification that the quality and reliability of the electronic systems met rigorous standards. However, with the growing consumer-oriented electronics content in today's vehicles, it is becoming more difficult for the automotive manufacturers to meet consumers' expectations with older technology. Couple this with the fast-paced consumer product cycle, typically nine to eighteen and the result is increasing pressure on the vehicle manufacturers from after-market electronics suppliers, who can update their product lines as fast as the component manufacturers can produce new models.

The thermal durability of a large frontal area cordierite ceramic wall-flow filter for light-duty diesel engine is examined under various regeneration conditions. The radial temperature distribution during burner regeneration, obtained by eight different thermocouples at six different axial sections of a 75″ diameter x 8″ long filter, is used together with physical properties of the filter to compute thermal stresses via finite element analysis. The stress-time history of the filter is then compared with the strength and fatigue characteristics of extruded cordierite ceramic monolith. The successful performance of the filter over as many as 1000 regenerations is attributed to three important design parameters, namely unique filter properties, controlled regeneration conditions, and optimum packaging design. The latter induces significant radial and axial compression in the filter thereby enhancing its strength and reducing the operating stresses.

Finite element methods can be used to simulate a class of variation problems induced by build distortion in the assembly process. The FEM approach was used to study two representative assembly problems: 1) Front fender mounting and resulting distortion due to various fastening sequences; and, 2) Coupe door assembly process and resulting deformation due to clamping and welding of flexible sheet metal parts. FEM is used to generate sensitivities of various process conditions. Correlation with measured Co-ordinate Measuring Machine (CMM) data is shown. The use of FEM to simulate manufacturing/assembly processes in the automotive industry is in it's infancy. As the new methods are developed this capability can be used to study the assembly process and provide guidance in designing more robust parts and assembly processes.

A driving simulator development project at the Systems Engineering and Technical Process Center (SE/TP) is exploring the role of driving simulation in the vehicle design process. The simulator provides two vehicle mockup testing arenas that support a wide field of view, computer-generated image of the road scene which dynamically responds to driver commands as a function of programmable vehicle model parameters. Two unique aspects of the simulator are the fast 65 ms response time and low incidence rate of simulator induced syndrome (about 5%). Preliminary model validation results and data comparing driver performance in a vehicle vs. the simulator indicate accurate handling response dynamics within the on-center handling region (<0.3g lateral acceleration). Applications have included supporting the development of new steering system concepts, as well as evaluating the usability of vehicle controls and displays.

For model year 1994, General Motors has completed the roll out of the 6.5L Diesel Engine, with the introduction of the light duty certified naturally aspirated and turbocharged engines. At the heart of the expanded use of the 6.5L is a new electronic powertrain control system. The objectives for this system were to produce an engine that has less variation, is easier to assemble, low cost and capable of meeting both heavy and light duty future emissions requirements. Control features include Fuel Quantity and Timing, EGR, Wastegate, Glow Plugs, Transmission, Cruise Control and Diagnostics.

The dilemma of using a shoulder belt force limiter with a 3-point belt system is selecting a limit load that will balance the reduced risk of significant thoracic injury due to the shoulder belt loading of the chest against the increased risk of significant head injury due to the greater upper torso motion allowed by the shoulder belt load limiter. However, with the use of air bags, this dilemma is more manageable since it only occurs for non-deploy accidents where the risk of significant head injury is low even for the unbelted occupant. A study was done using a validated occupant dynamics model of the Hybrid III dummy to investigate the effects that a prescribed set of shoulder belt force limits had on head and thoracic responses for 48 and 56 km/h barrier simulations with driver air bag deployment and for threshold crash severity simulations with no air bag deployment.

Several factors have influenced the size and design of domestic passenger cars over the past 30 years. Of most significance has been the influx of imported cars, initially from Europe, later from Japan. Interspersed within the fabric of this influx have been two energy crises and several recessions, and the onset of safety, emission, and energy regulations. These factors have led to various responses by domestic manufacturers as indicated by the types of products and vehicle systems that they have introduced during this period. This paper chronicles both the events as well as the responses.

THE 1957 Cadillac frame is a significant step in design progress toward the ever lower passenger cars demanded by customers and, therefore, car manufacturers. Stemming from tests and experimental designs in process since 1950, this frame combines reduction in height with a slight increase in structural efficiency. It reverses the trend toward the more costly and heavier structures usually associated with lower cars. Mr. Milliken discusses in Part I the steps Cadillac has taken in the last 19 years to reduce the height 9½ in. to 55½ in. The “Tubular Cenrer-X” frame of the 1957 Eldorado Brougham was the latest and most successful answer to the problem. In Part II Mr. Parker describes the A. O. Smith Corp.'s development of the basic idea and the experimental phases and testing which led to the production designs.

THIS paper describes the springs, control system, and ride of the air suspension system on the 1958 Buick. The system is a semiclosed one, providing a variable-rate suspension, automatic leveling and trim control, and manual lift. The latter feature is a knob below the instrument panel which can be operated when necessary to cope with unusual clearance conditions. The car remains at the same height with loads of up to five passengers and 500 lb in the trunk. The authors describe the road-holding ability of a car with this suspension system as excellent.

This paper describes the performance attributes of the all-new front and rear SLA (short-long arm) suspensions, steering system, and tires of the 1997 Corvette. The process by which these subsystem attributes flowed down from vehicle-level requirements for ride and handling performance is briefly described. Additionally, where applicable, specific subsystem attributes are rationalized back to a corresponding vehicle-level performance requirement. Suspension kinematic and compliance characteristics are described and contrasted to those of the previous generation (1984 to 1996 Model Year) Corvette. Both synthesis/analysis activities as well as mule-level vehicle development work are cited for their roles in mapping out specific subsystem attributes and related vehicle performance.

This paper describes some methods for greatly reducing or possibly eliminating subjective tuning of suspension parts for ride and handling. Laptop computers can now be used in the vehicle to guide the tuning process. The same tools can be used to select solutions that reduce sensitivity to production and environmental variations. OBJECTIVE Reduce or eliminate time required for tuning of suspension parts for ride characteristics. Improve the robustness of ride performance relative to variations in ambient temperature and production tolerances. PROBLEM REQUIRING SOLUTION AND METHOD OF APPROACH Traditional development programs for new vehicles include time-consuming subjective ride evaluations. One example is shock absorber tuning. Even if sophisticated models define force-velocity curves, numerous hardware iterations are needed to find valvings that will reproduce the curves. Many evaluation rides are needed to modify the valvings to meet performance targets.

This paper summarizes the rationale used to specify the geometric, inertial and impact response requirements for a small adult female dummy and a large adult male dummy with impact biofidelity and measurement capacity comparable to the Hybrid III dummy, the most advanced midsize adult male dummy. Body segment lengths and weights for these two dummies were based on the latest anthropometry studies for the extremes of the U.S.A. adult population. Other characteristic body segment dimensions were calculated from geometric and mass scaling relationships that assured that each body segment had the same mass density as the corresponding body segment of the Hybrid III dummy. The biomechanical impact response requirements for the head, neck, chest and knee of the Hybrid III dummy were scaled to give corresponding biomechanical impact response requirements for each dummy.