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1974 Automotive Engineering Congress and Exposition
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Scarcity and Social Accountability: An American Perspective on New Priorities for the Automotive Engineer

W. A. Gebhardt
Published 1974-05-01 by SAE International in United States
The engineer's traditional task of finding the best, most economical solution to technical problems becomes vastly more demanding in a time of energy and materials scarcity. Adaptability, flexibility, and quick access to suitable alternatives will acquire new significance in the next decade. Conservation measures, such as recycling, remanufacturing, and design for production and operational efficiency will increasingly figure in the development of transportation products.Beyond these and other changes in design emphasis lies a rising clamor for engineering accountability. Product liability legislation, many costly court decisions, and increased governmental regulation of many aspects of design all indicate growing public concern with the consequences of new technology. The trend toward establishing agencies for technology assessment will allow the engineer to participate in the evaluation of his designs in terms of their long-term social and economic impacts.
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Analytical Studies of the Head Injury Criterion (HIC)

Biomechanics Research Center, Wayne State Univ.-Clifford C. Chou
Research Laboratories, General Motors Corp.-Gerald W. Nyquist
Published 1974-02-01 by SAE International in United States
The Head Injury Criterion (HIC) in FMVSS 208 for evaluating the potential head injury requires maximization of a mathematical expression, involving the time-average acceleration, by varying the limits (t1, t2) of the time interval over which the average is calculated.This paper describes the HIC behavior through the analysis of a function of two independent variables t1 and t2. The analysis is carried out for any arbitrary acceleration profile a(t). It is found that maximization requires that a(t1) = a(t2). Also, for the unique values of t1 and t2 that maximize HIC, the average acceleration between t1 and t2 is 5/3 times the acceleration at t1 or t2. Illustrative examples are provided by applying this condition to simple pulses. Numerical results are presented in tables and graphs.
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Interregional Analysis of United States Freight Shipments

Department of Urban Studies and Planning, Massachusetts Institute of Technology-Karen R. Polenske
Published 1974-02-01 by SAE International in United States
This paper discusses the United States multiregional input-output model. The model is a flexible technique of analysis that can be used for many different regional economic studies. To illustrate its use, a description is given of the application of the model in an analysis of the regional and industrial interrelationships between the transportation and energy sectors of the American economy.
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Design and Development of a Variable Valve Timing (VVT) Camshaft

Environmental Activities Staff, General Motors Corp.-Carl A. Schiele
Research Laboratories, General Motors Corp.-Stephen F. DeNagel, James E. Bennethum
Published 1974-02-01 by SAE International in United States
The development of a variable valve timing (VVT) camshaft was initiated as a potential means of controlling exhaust emissions from a spark ignition piston engine. This approach was based on the fact that valve overlap influences internal exhaust gas recirculation which in turn affects spark ignition engine emissions and performance. The design, fabrication, bench tests and engine durability tests of a unit incorporating splines to allow the intake cams to move relative to the exhaust cams is discussed. Preliminary test data from a 350 CID (5700 cm3) engine fitted with the VVT camshaft are discussed with regard to durability and emissions.
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Actuating Devices for Electronic Controlled Systems

Essex International, Inc., Detroit, Michigan.-Frank Berger
Published 1974-02-01 by SAE International in United States
The output signals from electronic circuits in suggested computerized systems can seldom be used directly to accomplish intended results in a vehicle. It is necessary to introduce a device that must transduce or amplify this signal as instructed by the electronic controls. These devices can be electromechanical, electromagnetic, or electrofluidic in nature. The intent of this paper is to describe these devices and their intended use in a system and to suggest criteria in order to select the proper device for desired results.
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A New Kind of Radar for Collision Avoidance

RCA Corp.-J. Shefer, R. J. Klensch, H. C. Johnson, G. S. Kaplan
Published 1974-02-01 by SAE International in United States
An experimental automobile radar has been demonstrated which is designed to avoid rear end collisions on highways. A completely passive reflector, mounted on the back of vehicles, returns the second harmonic of the frequency transmitted from the trailing vehicle. The radar is immune to clutter since its receiver is tuned to the second harmonic frequency only. It is also immune to blinding by cars traveling in the opposite direction, as well as to other interference problems inherent in a dense environment.
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Universal Engine Oils: Prime Quality for Prime Movers

Shell Development Co.-Danford H. Olson
Published 1974-02-01 by SAE International in United States
To meet the needs of fleet operators, engine crankcase oils for use in gasoline, nonturbocharged 2- and 4-cycle and turbo-charged 2- and 4-cycle diesel engines have been developed by the oil industry. This paper reviews the laboratory and field performance of a 1.0% wt ash universal oil in gasoline and diesel engine powered trucks. Excellent field performance was documented by analysis of engine maintenance records from several truck fleets.
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The Effect of Changes in Design and Operating Conditions on Heat Release in Direct-Injection Diesel Engines

School of Engineering, University of Bath (England)-J. B. Way
University of Manchester Institute of Science and Technology (England)-N. D. Whitehouse, E. Clough
Published 1974-02-01 by SAE International in United States
Heat release data have been obtained from a 5 in bore direct injection diesel engine operating over a range of conditions including off-design conditions, such as running at low air to fuel ratios, using six-hole injector nozzles in place of the standard three-hole nozzles, and reducing compression ratio and thereby swirl ratio at tdc.The paper shows that when operating with adequate utilized air fuel ratios (A/Fs) the experimental heat release data could be correlated with a single zone combustion model and that changing the number of nozzle holes or compression/swirl ratio had little effect on the correlation after the initial period of heat release.At inadequate A/Fs a modification to the model to allow for partial combustion was introduced. This improved correlation and enabled reasonable heat release prediction in the cycle synthesis program.Examples are given of heat release and cycle pressure diagrams computed using these models.
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Relationship Between Spark Plugs and Engine-Radiated Electromagnetic Interference

AC Spark Plug Div., General Motors Corp.-Richard R. Burgett, Richard E. Massoll, Donald R. Van Uum
Published 1974-02-01 by SAE International in United States
The ignition system of any spark-ignited internal combustion engine-powered device is well recognized as a major source of radiated electromagnetic interference (EMI). Spark plug designs can be selected to aid in reducing ignition-related EMI. The effects of various spark plug designs such as resistor spark plugs, inductor spark plugs, and shielded spark plugs upon both EMI and ignition system performance are presented. In addition to studying the effect of spark plug design, the use of the SAE standard (J551b) and other EMI measurement techniques to determine effect of spark plug suppression designs are discussed. Generally, the addition of a resistor to the spark plug provides the most effective spark plug suppression. However, other designs may be effective as an addition to the resistor or as a substitute where resistors cannot be practically used.
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Occupant Protection in Car-to-Car Impacts

Engineering Staff, General Motors Corp.-Raymond G. Fischer
Published 1974-02-01 by SAE International in United States
An analytical study defines the interaction of the occupant and the vehicle as a system for car-to-car impacts.Using basic relationships, the question of vehicle stiffness and mass differential effects on the occupant is discussed. The vehicle characteristics used for the car-to-car impacts are developed from barrier impact data.
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