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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.

Chrysler is a company run by automotive enthusiasts, and its motorsports programs are an integral part of the company's corporate, brand, and product development process. Chrysler's motorsports programs are executed from within its Platform Team system by the same engineers, using the same processes and facilities as production vehicle programs. This results in teaching and inspiring engineers, designers, and technicians, as well as providing genuine technical benefits to the company. This paper tells the “how” story of the design, build, and test of the Dodge Stratus Super Touring Car. Detailed results have been purposely omitted from the paper due to the competitive nature of motor racing.

PLYMOUTH'S new V-8 engine has a specific output of 0.65 bhp/cu in. and 145-psi bmep — obtained through a combination of high thermal, volumetric, and mechanical efficiencies. Good design, the author points out, has achieved this high output despite the dual-venturi carburetor and the 7.6/1 compression ratio, selected for satisfactory operation on regular-grade fuels. The engine has a bore and stroke of 3.563 × 3¼, weighs 568 lb without flywheel, is 29⅜ in. long, and is designed for optimum response to future compression ratio increases. (A report of oral discussion following presentation of this paper appears on p. 220, following “The New Packard V-8 Engine,” by W. E. Schwieder.)

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.

Most of the current fuel supply specifications, including the key parameters in the transient fuel control strategies, are experimentally determined since the complexity of multiphase fuel flow behavior inside the intake manifold is still not quantitatively understood. Optimizing these specifications, especially the parameters in transient fueling systems, is a key issue in improving fuel efficiency and reducing exhaust emissions. In this paper, a model of fuel spray, wall-film flow and wall-film vaporization has been developed to gain a better understanding of the multiphase fuel-flow behavior within the intake manifold which may help to determine the fuel supply specifications in a multi-point injection system.

An automotive cockpit module is a complex assembly, which consists of components and sub-systems. The critical systems in the cockpit module are the instrument panel (IP), the floor console, and door trim assemblies, which consist of many plastic trims. Stiffness is one of the most important parameters for the plastic trims' design, and it should be optimum to meet all the three functional requirements of safety, vibration and durability. This paper presents how the CAE application and various other techniques are used efficiently to predict the stiffness, and the strength of automotive cockpit systems, which will reduce the product development cycle time and cost. The implicit solver is used for the most of the stiffness analysis, and the explicit techniques are used in highly non-linear situations. This paper also shows the correlations of the CAE results and the physical test results, which will give more confidence in product design and reduce the cost of prototype testing.

Simultaneous engineering methods are being used in automotive engineering. A brief explanation of the method and benefits are presented. Merging the methodology with new organizational structures provides greater advantages. A discussion of the benefits and future directions are presented.

This paper describes the ride and handling development process used for the 1997 Corvette. Three levels of suspension are available for the 1997 Corvette: base (FE1), sport (FE3) and RTD or Real Time Damping (F45) suspensions. All suspensions will be discussed in this paper A review of the development and vehicle integration tradeoffs for each of the specific chassis components is included. Control arm bushings, springs, jounce bumpers, anti-roll bars and insulators, tires, shock mounts, shock absorber valving, real-time damping, steering development, alignment and measurements are discussed.

A rear full overlap car-to-car high speed impact simulation using the DYNA3D Finite Element Software was performed to examine the crush mode for rear structure of a vehicle and to observe the effect of rear bumper system in order to maintain the fuel system integrity. The study was conducted first for two different bumper system configurations, namely: (1) validating the model for struck vehicle with steel rear bumper system, (2) simulating rear end collision with composite rear bumper system attached to the rear rails of struck vehicle. Later a third simulation of the model was conducted with a viable design modification to the composite bumper system for improved crashworthiness. It was identified that a more comprehensive FEA model of the bullet car including front end structure, powertrain components, cooling system and other components which constitute the load paths should be incorporated in the analysis to obtain more meaningful correlation and crashworthiness prediction.

There are important changes unfolding in domestic industry. In the face of increased competition and the reality that traditional practices are no longer sufficient, manufacturers are taking daring new looks at the ways that they do business. Platforms and small business units are being formed within large companies to manage product lines. Cross-functional teams are replacing functional organizations as the driving forces in product development. Authority and leadership are being shifted lower and lower Into the working ranks, and the reengineering of work processes is becoming the challenge. This paper presents part of the story of Chrysler's Small Car Platform. It begins with an overview of the platform system. Then it focuses on the Process Phase of a vehicle program. The story is told to illustrate our experience in a continuous improvement process.

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.

A gasoline direct injection fuel spray was observed using a fired, optical access, square cross-section single cylinder research engine and high-speed video imaging. Spray interaction with the piston is described qualitatively, and the results are compared with Computational Fluid Dynamics (CFD) simulation results using KIVA-3V version 2. CFD simulations predicted that within the operating window for stratified charge operation, between 1% and 4% of the injected fuel would remain on the piston as a liquid film, dependent primarily on piston temperature. The experimental results support the CFD simulations qualitatively, but the amount of fuel film remaining on the piston appears to be under-predicted. High-speed video footage shows a vigorous spray impingement on the piston crown, resulting in vapor production.

The automobile industry has been using high-density polyethylene (HDPE) as a material to fabricate fuel tanks. Because untreated HDPE is permeable to the primary constituents of gasoline, these fuel tanks are now being produced with various barrier technologies that significantly reduce this permeation rate. Four currently available barrier technologies are fluorination, sulfonation, coextrusion, and the laminar barrier technology. These technologies have successfully proven to decrease the permeation rate of pure gasoline. However, it is suspected that their effectiveness may be reduced when alcohols are introduced into the fuel blend. In this work, we determine the permeation rates of gasoline-alcohol fuel blends through HDPE by conducting tests on 22-gallon HDPE fuel tanks and on small HDPE bottles fabricated with and without these barrier technologies. The goal of this study is to provide a comprehensive evaluation of these four barrier technologies.

A sealed plastic enclosure was proposed in February 1967 by HEW as a technique for measurement of fuel system evaporative emissions from an automobile. Early work with this technique uncovered problems such as car background emissions. Subsequent experimental work, however, has solved these problems and has shown the sealed enclosure capable of correctly measuring total vehicle evaporative emissions. Fuel vapors that actually reach the atmosphere can be measured in a simple, direct way without the necessity for vehicle modification. A complete description of the enclosure is given and its use by GM is described.

FIGURE 1 The 200 HP high performance 4.3L Vortec V6 engine has been developed to satisfy the need for a fuel efficient performance powerplant in the General Motors small truck platforms. Marketing requirements included strong low and mid range torque, relatively high specific power, smoothness and noise comparable to the best competitive six cylinder engines, excellent driveability, and a new technology image. Maintaining the 4.3L engine record of high reliability and customer satisfaction was an absolute requirement. Fuel economy and exhaust emission performance had to meet expected customer and legislated requirements in the mid 1990's.

Properly implemented, On-Board Diagnostic (OBD) Systems fill the gap in sophistication between computer based fuel injection engine controls and a carburetor oriented service industry. By emphasizing simplicity and credibility, inexpensive OBD systems make electronic engine controls a desirable feature to the service technician.

This paper describes the hardware execution of the front and rear suspensions of the all new 1997 Chevrolet Corvette. Topics covered include: alternative design trade-off, mass optimization, alignment and trim, structural interfaces, shared components, component design and a review of the overall design of the front and rear suspensions. Two case studies are detailed for the front upper and rear lower control arms. The systems engineering process used for suspension design is described throughout the paper.

The rear cross-car stiffener subsystem is generally located at the underside of the rear compartment pan of a car body and connects the two rear longitudinal rails or rear rockers. The primary purpose of this subsystem is to maintain structural integrity as well as fuel system integrity in a rear angle impact or dynamic side impact collision. To evaluate the effect of this subsystem on lateral crashworthiness in a high speed angle impact, a finite element model consisting of the cross-car bar, a portion of rear compartment pan and both rear rails was developed and analyzed with the DYNA3D crashworthiness simulation software. Thus, the cross-car stiffener subsystem design including the welding pattern was finalized and the acceptable design was successfully implemented in the vehicle. Subsequently drop silo tests were carried out to further verify the design and to improve the manufacturing process.

This paper presents a method for developing a product design and manufacturing process concept, before project final approval, which integrates several other methodologies and uses cross-functional teams. It is a method for completing a “paper” study which quickly considers many of the downstream steps of product development, which will be conducted in greater detail later. It results in a selection of the best design and process for the overall product application and supports this selection with sound numerical targets for quality, cost, weight, investment and process capability.

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.