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Technical Paper

Requirements for Improved Battery Design and Performance

Smaller, hotter engine compartments, increased electrical loads, and stringent customer requirements place ever increasing demands on automotive battery performance. Current battery designs and shortcomings are discussed as well as the necessity for improved designs. Topics also include temperature effects, state of charge, charge efficiency, customer usage and requirements, battery age, and dealership handling practices. Present SAE test procedures are reviewed and new rating requirements are suggested to meet today's vehicle applications. Special dealership programs also reveal various methods to improve performance. In addition, power and thermal management for tomorrow's vehicles is discussed. The supporting documents are compiled from various studies conducted between 1984 and 1988 encompassing over 5,000,000 Chrysler vehicles. The data reflects direct comparisons from the field on a warm versus cold climate basis.
Technical Paper

Evaluation of Control Cooled, NB-Treated SAE 1141 steel Connecting Rod

Material properties of niobium (Nb)-treated SAE I 141 steel connecting rod produced by control cooling were evaluated in comparison with quenched and tempered connecting rod of the same steel. The microstructure of the control cooled connecting rod is predominantly bainitic compared with tempered martensite for the quenched and tempered rod. Tensile strengths are comparable, while yield strength and ductility are lower for the control cooled connecting rod. There are small variations in hardness of the control cooled connecting rod depending on the section thickness in contrast with the uniform hardness for the quenched and tempered rod. Component high-cycle fatigue resistance is lower for the control cooled connecting rod due to the lower yield strength. Both connecting rods meet the fatigue strength performance requirements for the rod design evaluated.
Technical Paper

Machinability Evaluation of Crankshaft Bearing Cap Materials

THIS STUDY WAS DEVELOPED in response to a component fatigue strength test which determined that if the current #3 engine bearing cap were used in the 2.5L Turbo application, it would be over stressed. Proposed solutions for solving this problem included: a redesigned grey iron cap with additional material in the highly stressed areas, or a cap made from either nodular iron or a free machining steel using current specifications. One of the manufacturing concerns about switching materials is the perceived difference in the machinability of nodular iron and steel. A single point turning evaluation was carried out by Chrysler Motors' Machinability Development Laboratory to compare the machinability of various materials proposed for use in engine bearing caps. Materials tested included: SAE G2500 grey cast iron, the current production material; SAE D45-12 nodular cast iron; and SAE steel grades 1117, 1137, 1215, 12L14, 1215, and 1215 modified (Incut 200).
Technical Paper

Concept Design on a MCAE Workstation - A User's Viewpoint

A Mechanical Computer-Aided Engineering (MCAE) workstation supplied as a Beta test unit by the Aries Corporation was evaluated in the concept design process. This unit had six software modules including materials database, solid modeler, mass and section properties, and finite element analysis program, and finite element post-processors. Specific applications and the user experience with the configured workstation are presented.
Technical Paper

Plastic Bumper Beam Manufacturing Analysis

The manufacturing analysis of molded plastic parts is described in detail. A PC based program is presented to analyze the material and capital cost. The program listing is included.
Technical Paper

The All-Adaptive Controls for the Chrysler Ultradrive Transaxle

THE NEW CHRYSLER ULTRADRIVE four-speed transaxle is the first production transmission to employ fully-adaptive electronic controls. Adaptive controls are those which perform their functions based on real-time feedback sensor information, just as is done by electronic anti-skid brake controls. Although the transmission is conventional in that it uses hydraulically-applied clutches to shift a planetary geartrain, its use of electronic logic to replace the function of many mechanical and hydraulic components is unique. This paper describes the adaptive controls, how they function in upshifts and downshifts, the simplicity they permit in the clutch and geartrain arrangement, their effect on the design of certain components, and the advantages they offer in diagnostics. It also describes the hydraulics and how certain unique challenges are met in the Ultradrive transmission.
Technical Paper

What Every Engineer Should Know About Finite Element Analysis Methods

The scope of Finite Element Analysis in the Product Development Cycle is given. A brief review of the development process is given. A brief description of the analysis method is presented. A description of how it works, how is it implemented, and where do I use it are included. The entire range of questions are answered through, how do I train for it, how do I manage it, along with what are the limitations and what are the benefits of this analysis method.
Technical Paper

Effects of Steel Surface Texture on Appearance After Painting

An extensive investigation was conducted to assess the influence of steel sheet surface finish (i.e. topography or “texture”) on painted surface appearance. Ten sets of steel panels representing a variety of shot blast, EDT, laser, and bright surface textures were painted simultaneously using advanced solvent-based luxury vehicle paint systems. Paint appearance was measured using a relatively new Autospect instrument and also in terms of conventional Distinctness of Reflected Image (DOI). The results are discussed in detail with respect to 1) the influence of different steel surface textures on paint appearance, 2) the evolution of surface topography during painting, and 3) the implications of this work.
Technical Paper

An Experimental Study of In-Cylinder Air Flow in a 3.5L Four-Valve SI Engine by High Speed Flow Visualization and Two-Component LDV Measurement

In-cylinder flows in four-valve SI engines were examined by high frame rate flow visualization and two-component LDV measurement. It is believed that the tumble and swirl motion generated during intake breaks down into small-scale turbulence later in the cycle. The exact nature of this relationship is not well known. However, control of the turbulence offers control of the combustion process. To develop a better physical understanding of the in-cylinder flow, the effects of the cylinder head intake port configuration and the piston geometry were examined. For the present study, a 3.5L, four-valve engine was modified to be mounted on an AVL single cylinder research engine type 520. A quartz cylinder was fabricated for optical access to the in-cylinder flow. Piston rings were replaced by Rulon-LD rings. A Rulon-LD ring is advantageous for the optical access as it requires no lubrication.
Technical Paper

Improving the Product/Process Relationship

Product Engineering, Component Supply and Vehicle Assembly are the main forces that transform ideas, customer research and technical information into products. Quality professionals, and others, have advanced many concept models about improved Product and Process Development based upon the application of new tools and systems to Engineering, Procurement/ Supply and Manufacturing/Assembly relationships. Regardless of the concept model, the problem of effecting operating change in U.S. automotive business practices has both behavioral and technical implications. While many studies have emphasized the application of quality tools and systems as a means to improve Product/Process development, they often overlook the cultural change that is necessary to transition from a 75-year history of strong vertical organizations to the “Networking” implicit with new concept models. The availability of improved tools and systems alone will not insure behavioral change.
Technical Paper

What Every Engineer Should Know About Solid Modeling

A brief description of part creation on the computer by solids is presented. The capabilities, use, and benefits of this method in the product development cycle is given. Solid modeling as the basis for downstream C A E work and specific examples are discussed.
Technical Paper

Manufacturing Techniques for Composite Materials - Current and Future Automotive Trends

Process Driven Design yields proven benefits in automotive product design. The use of plastics is expanding in the automotive industry. The designer requires a knowledge of the methods of processing plastic parts. This work provides this information by giving a brief description of plastic processing techniques. Included in this is an extensive table of processing techniques and current parts fabricated by these methods. Extension of the process to future automotive products is included.
Technical Paper

Effects of Gasoline Composition on Evaporative and Running Loss Emissions - Auto/Oil Air Quality Improvement Research Program

Evaporative and running loss emissions were measured in a fleet of ten (1 989) current and seven (1983-85) older vehicles with fuels whose compositions varied in aromatic, olefin, and MTBE content and 90 percent distillation temperature (T9O). Emission compositions from each test were analyzed for individual hydrocarbon species. The individual hydrocarbon profiles were used to calculate evaporative and running loss emission reactivities using Carter maximum incremental reactivity (MIR) and maximum ozone reactivity (MOR) scales. Ozone reactivity estimates were expressed as Ozone Forming Potential (gO3/test) and Specific Reactivity (gO3/gNMOG) for both reactivity scales. The data were analyzed by regression analysis to estimate changes in the mass and reactivity of evaporative emissions due to changes in fuel composition. Previous studies have focused on how fuel volatility affects evaporative emissions without regard for the chemical composition of the fuels.
Technical Paper

Variable Orifice Valve Development and A/C System Performance Testing

First introduced in 1995, the concept of a temperature-responsive Variable Orifice Valve to control refrigerant flow (patent # 5,479,786) has been further developed for use in automotive refrigerant systems. This device is an alternative, to the expansion devices currently used in automotive refrigerant systems and offers the best features of a thermal expansion valve system (similar high ambient performance ) and of a fixed orifice tube system (low cost, high reliability & performance at lower ambients). Typical automotive refrigerant system operation includes wide variations in condenser air flow and refrigerant pressure. The resultant condenser exit refrigerant temperature is a very stable input parameter for the control of this variable orifice valve (VOV).
Technical Paper

Reduction of Passenger Car Road Noise Using Computational Analysis

The noise within a car interior affects the customers' perception of quality, hence the need for noise control in cars. The arrival of structural finite element analysis (FEA) and acoustic boundary element analysis (BEA) has created the possibility of quickly performing many computational design changes. Thus, effective noise control solutions can be predicted without many vehicle prototypes. Computational analysis of the passenger compartment of an existing four-door car was performed to predict and reduce road noise. This analysis guided the development of structural changes that would reduce the sound pressure levels at the driver's and rear passenger's ear locations. Laboratory tests of these structural modifications in a prototype vehicle confirmed that the sound levels were reduced.
Technical Paper

Emissions with E85 and Gasolines in Flexible/Variable Fuel Vehicles - The Auto/Oil Air Quality Improvement Research Program

Exhaust and evaporative emissions from three flexible/variable fuel vehicles (FFV/VFV) were measured as the vehicles operated on E85 fuel (a mixture of 85% ethanol and 15% gasoline) or on gasoline. One vehicle was a production vehicle designed for ethanol fuels and sold in 1992-93 and the other two vehicles were prototypes which were recalibrated 1992 model year methanol FFV's. The gasolines tested were Industry Average Fuel A and a reformulated gasoline Fuel C2 that met California 1996 regulatory requirements. The gasoline component of Fuel E85 was based on the reformulated gasoline. The major findings from this three-vehicle program were that E85 reduced NOx 49% compared to Fuel A and 37% compared to Fuel C2, but increased total toxics 108% (5 mg/mi) and 255% (20 mg/mi), respectively, primarily by increasing acetaldehyde. The NOx effect was significant for both engine-out and tailpipe emissions.
Technical Paper

The Development of a Knowledge-Based System for the Nondestructive Inspection of Composites

The increased use of a wide variety of recently developed engineered materials and associated processes, for producing vehicular components, has posed a significant challenge to those charged with the responsibility of knowing, developing and/or applying inspection and testing technology to support the quality assurance of these materials, processes and resulting products. This challenge can be more easily and effectively met, within the constraints of time, expertise and other available resources, if computerized knowledge-based systems are employed to enhance the identification, acquisition and application of advanced inspection technology. This paper provides an overview of developments underway to implement this approach in an automotive environment.
Technical Paper

Need for PC Based Programs in Vehicle Design

The need for personal computer based programs for vehicle design is shown by a literature search. These programs must be easy to use to permit the running by engineers and designers early in the concept design cycle. The range of typical programs available and needed is given.
Technical Paper

The Chrysler A-604 Ultradrive 4-Speed Automatic Transaxle

A new kind of four-speed automatic transaxle, engineered from concept specifically for real-time closed-loop electronic control, has been designed, developed, and put into production by Chrysler Motors Corporation. This overdrive transaxle combines two simple planetary gear sets with five disc-clutches, five hydraulic spool valves, and four direct-acting three-way solenoid valves to achieve all operating modes. It uses no bands and only the torque converter stator has a freewheel element. It provides both a fourth ratio and increased engine torque capacity in the same package space used by the previous three-speed transaxle. At the same time, fewer parts are required and manufacturing is more readily automated.