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Technical Paper

Powertrain Applications for Rapid Prototyping, Fabrication and Tooling in Motorsports

Rapid Prototyping, Fabrication and Tooling is a process that blends a series of technologies (machines, tools, and methods) capable of generating physical objects directly from a CAD database. The process dramatically reduces the time spent during product development by allowing for fast visualization, verification, iteration, optimization, and fabrication of parts and tools. Many new techniques of tooling have been and are being developed by using rapid fabricated parts. These are having a dramatic impact on both timing and costs throughout the automotive industry. One area that these methods can be utilized to their full potential is motorsports. Of particular interest is the growing use of bridge tooling to provide first article through production intent parts that promote cost effective changes.
Technical Paper

Composite Impact Analysis of Race Cars - Technology Transfer to Passenger Car Development

There are a number of benefits from Ford Motor Company's participation in motorsports. This paper will describe how an engineering team developed a CAE process to assist in the design of a race car to meet impact requirements, with the technology transfer benefit of improved impact performance of composite structures in passenger cars. In 1997/98, a CAE process was developed and applied in the design and test of Formula One race car composite impact structures. For this particular engineering effort, a Ford proprietary software program, COMP-COLLAPSE, was the primary analysis tool that was utilized to successfully predict impact performance. As a result, COMP-COLLAPSE was used extensively in the design of race car composite impact structures. There were two beneficiaries from this effort: Race Vehicles: Improved vehicle impact performance as well as design improvement in crush efficiency, packaging, weight, and manufacturing.
Technical Paper

Enhanced Machining Center Accuracy Through Real Time Error Compensation

There is an ever increasing demand on part quality and tighter tolerances for machining of components in high volume manufacturing. A major source of problem in the machine tools is the thermally induced error due to thermal gradients and uneven heating and expansion of various machine components. Current practice of manufacturing precision parts involves periodic gaging of parts, whereby, production is interrupted and manual compensating offsets are input to the controller. Also, additional production costs are introduced due to requirement of initial warm up cycles without cutting parts and utilization of chillers for temperature controlled coolants. In this paper, a methodology is described for automatic compensation for thermal error by means of components/locations temperature profile and calculated error between the tool tip and the workpiece.
Technical Paper

Drill Breakage Elimination by Closed Loop Torque Control

This paper summarizes the design and implementation of a model-based torque control strategy for drilling. During drilling, the torque often increases due to difficulties with chip evacuation from the drill flutes. Excessive torque can accelerate tool wear or cause torsional failure of the drill. To avoid problems associated with excessive torque, closed loop torque control by manipulation of feedrate was pursued. This strategy simultaneously avoids tool breakage and decreases the cycle time compared to conventional practice. There can be significant cost benefits of torque control due to eliminating tool breakage. For example, reductions in scrap, rework, and machine maintenance costs may be realized. Dynamic models were developed for the drive system, sensing system, and drilling process. These models were subsequently used to design a model-based torque control strategy. Experimental results are presented for conventional twist drilling and form tool drilling applications.
Technical Paper

Drilling Burr Characterization Using Semantic Differential Method

The semantic differential (SD) method was used to characterize the size and shape of burrs created under various cutting conditions, drill size, tool geometry and coatings. Human subjects visually rated the burr using a SD evaluation form. Significant differences were found in tool type and feed rate. A high performance drill with titanium-nitride coating and a high depth/diameter ratio, yielded minimum burr. A lower feed rate resulted in less burr formation in the majority of the cases. Three primary factors emerged, and accounted for 83% of the variances. Factor scores were mapped into the SD space to show the effect of treatments.
Technical Paper

Ford's 1996 Crown Victoria Dedicated Natural Gas Vehicle

Ford Motor Company has introduced a Crown Victoria dedicated natural gas vehicle (NGV) to meet rising demand for vehicles powered by cleaner burning fuels and to reduce dependency on foreign energy imports. The Crown Victoria NGV is a production vehicle maintaining Original Equipment Manufacturer (OEM) quality and warranty while complying with all applicable corporate, federal and state requirements.
Technical Paper

A Novel Approach to Statistical Energy Analysis Model Validation

Statistical Energy Analysis (SEA) is a tool for estimating the response of complex dynamic systems at high modal density. This tool is seeing ever wider application in a range of industries, including aerospace industry, marine industry, and building trades. The automotive industry is beginning to explore the application of SEA to high frequency vehicle acoustic design. The SEA model of vibrational power transmission has a direct analogy to thermal power transmission (diffusion). As thermal power flow is proportional to temperature difference, vibrational power flow is proportional to modal energy difference. In this paper the thermal analogy is exploited to visualize the SEA results. This is accomplished by color coding a finite element representation of the structure. In this paper, the thermal analogy is used to correlate test data with SEA model results. This is accomplished by constructing a test based modal power thermogram.
Technical Paper

Measurement of Aeroacoustically Induced Door Glass Vibrations Using a Laser Vibrometer

Work has been performed to study side glass vibrations of a typical automobile using a scanning laser vibrometer. The objective of this work was to achieve better understanding of the source and path mechanisms for aeroacoustically generated wind noise. As a tool for measuring aeroacoustically generated vibrations, the laser vibrometer presents many advantages over traditional methods. These advantages, discussed in this paper, include rapid setup, full field imaging, high spacial resolution, non-contact operation, and wide dynamic and frequency ranges.
Technical Paper

Application of Operating Deflection Shape Analysis of a Powerplant Over the Entire Operating Speed Sweep to Provide an Insight to the Structural Behavior of the System

Operating Deflection Shape (ODS) [1][2] analysis is a useful tool to analyze vibration characteristics of a total powerplant. ODS analysis was used to analyze a powerplant during a speed sweep at a constant operating condition. The results show global bending shapes of the powerplant. These shapes can be analyzed in terms of order or speed to highlight important characteristics and their impact on the powerplant itself as well as the full vehicle.
Technical Paper

An Analytical Prediction of Water Droplet Travel when Discharged from the Face of an Evaporator Core

Here we present an analytical model, written in general terms, which predicts the trajectory of a spherical particle/droplet placed in a uniform fluid stream. The model is compared to an experiment in which three millimeter diameter polypropolyene spheres (specific gravity = 0.91) are dropped in a uniform airstream (velocity varies from 0.9 to 3.8 m/s). Agreement between the two suggests the model incorporates all the important physics and thus should be useful as a design tool.
Technical Paper

A Comparison of Time Domain and Frequency Domain Test Methods for Automotive Components

Frequency domain testing has had limited use in the past for durability evaluations of automotive components. Recent advances and new perspectives now make it a viable option. Using frequency domain testing for components, test times can be greatly reduced, resulting in considerable savings of time, money, and resources. Quality can be built into the component, thus making real-time subsystem and full vehicle testing and development more meaningful. Time domain testing historically started with block cycle histogram tests. Improved capabilities of computers, controllers, math procedures, and algorithms have led to real time simulation in the laboratory. Real time simulation is a time domain technique for duplicating real world environments using computer controlled multi-axial load inputs. It contains all phase information as in the recorded proving ground data. However, normal equipment limitations prevent the operation at higher frequencies.
Technical Paper

Comparison of Engine Dynamometer Test Procedures

A comparison between ‘Quasi-Transient’ and Steady-State (SAE J1349) engine dynamometer horsepower test procedures was conducted to determine the degree of correlation between the two test methods. Measurements demonstrated that the peak horsepower and torque measured using both techniques was similar. This information is useful as a development tool, because the ‘Quasi-Transient’ procedure allows for data to be collected over the engine RPM range much faster then the Steady-State method, allowing for the accurate testing of more engine/exhaust configurations in a shorter amount of time.
Technical Paper

Durability by Design - An Overview

An overview of the current status and emerging trends in durability-related technologies is presented as an introduction to a series of papers covering applications of durability analysis in design. Problems of information management associated with technology integration are discussed along with the probable impact of new design tools on product development and validation.
Technical Paper

Comparison of Electric and Pneumatic Power Tools - Part I: Mechanical Characteristics and Cost

Each supplier in the power tool industry offers unique tool features and packages. Competition and widespread individuality among manufacturers make it difficult to compare current air and new DC electric power tools. This experimental study compares air and electric hand-held tools based on laboratory testing and research of significant tool characteristics including heat buildup, tool impulse, cycle time and cost. Heat buildup in electric tools raised concerns as well as tool speed, although electric tools were in some instances only slightly slower than air tools. Electric tools, in general, do not have a lower torque-reaction impulse than air tools, but the correlation between tool-shutoff impulse and operator comfort remains unclear. Electric tools are more energy efficient than pneumatic tools, but their initial investment cost greatly outweighs the payback through reduced power usage.
Technical Paper

Organizing the Engineer's Toolbox

QFD, FMEA, Process Improvement, Taguchi, Simultaneous Engineering, PDP, Project Management, DVP, DOE, …and the list goes on. Today's automotive product design engineers face a myriad of “tools” (methodologies, techniques, procedures) that are expected to be mastered and used in the course of performing their job. The list continually grows with new tools being added to the existing ones. And each new tool has an associated acronym to add to the confusion. New and inexperienced engineers are often confused by these tools being tossed at them …school did not cover all this ! The experienced engineer is often skeptical. After all, “if I have been a successful engineer for 20 years, why do I need to start doing these things now?” Nevertheless, most of these tools are truly needed by engineers today in order to be competitive in the increasingly complex and sophisticated world of automotive product design.
Technical Paper

Measurement of Acoustical Response of Automotive Cabin Interior

We report measurements of interior automotive cabin forced acoustical response (SPL) as a function of frequency from 1 Hz to 200 Hz. The acoustical response was measured at eight positions in the vehicle tested, approximating the positions of passengers and points in between passengers. Variances in experimental data arising from the manner in which measuring equipment is setup in a particular vehicle are reported, and variations in data taken in similarly equipped vehicles are also reported. The purpose of these tests is to determine the measurement variability of a typical vehicle acoustic test.
Technical Paper

CRC Vapor Lock Technique Its Development and Application (Report of Volatility Group, Motor Vehicle Fuel, Lubricant, and Equipment Research Committee of the Coordinating Research Council, Inc.)

In 1958 the Coordinating Research Council conducted an extensive series of vapor lock road tests at a centralized location to study the effect of test variables on the hot fuel handling characteristics of passenger cars. Two years later, another test program was carried out at a common location to determine the hot fuel handling characteristics of a selected group of 1960 cars, employing the vapor lock survey technique developed in the 1958 program. The results obtained from the two programs indicate that this technique provides a satisfactory basis for defining the more severe vapor handling characteristics of automobiles in a relatively short time.
Technical Paper

Development of Van Driver Eye Ellipses*

This study was undertaken to determine to what extent the passenger car eye ellipses have applicability in van-type truck package design and to produce a new practical design tool, if necessary. Eye positions of van drivers were found to be distributed differently from those for passenger car drivers and from those obtained by the procedure outlined in SAE J941b, Motor Vehicle Driver's Eye Range. There were produced in this study, tables of parameter values that a van-package designer can use readily to position eye-location distributions in space as a function of the azimuth and elevation angles of many targets in the forward field of view. These tables are available upon request from SAE.
Technical Paper

PLASTIC PROTOTYPES Revolutionize Preparation for Manufacture

ONE plastic model is worth 40 lb of blueprints and 40 hr of the explaining that goes along with the prints, according to engineers who have worked with the new plastic “toys” which can serve as perfectly scaled miniatures for virtually every phase of automobile design and manufacture. The extensive benefits occasioned by this revolution in methods may be summarized thus: 1. Shortens design development time by providing a third-dimension evolvement of structure and form. 2. Used in advance discussions for compromising engineering and manufacturing problems, showing construction so clearly that troublesome problems are foreseen; thus enabling clear-cut, reliable decisions with a minimized chance of encountering major revisions. 3. Show in one minute what could not be found on prints for hours, saving time over any other methods, while generating valuable counterproposals reducing costs, operations, man-hours, and so forth. 4.