Search Results

Attention in the United States is centering on investigations of lighter materials, more efficient structures, impact compatibility between cars, as well as between structure and restraints and simulation of collisions using both mechanical and computer techniques. This paper summarizes investigations as well as safety effects.

Obtaining vehicle fuel economy data in conjunction with chassis dynamometer emissions testing is a useful, convenient technique. Data derived in this manner, using EPA city and highway driving cycles, are in wide use. Fuel economy results obtained by carbon mass balance calculation of carbon containing compounds in the vehicle exhaust are at least as accurate and repeatable as those obtained by direct measurement of fuel consumed. Nevertheless, the overall chassis dynamometer-carbon balance fuel economy test yields undesirable variation of results and needs refinement. Major factors influencing the accuracy and repeatability of test results are: CO2 measurement accuracy; variations in following the driving cycle; vehicle-dynamometer interface conditions; and associated calibration, calculation, test technique and procedural methods and controls employed.

As part of its ESV evaluation effort, Dynamic Science has recently conducted vehicle-to-vehicle aggressive testing of the large AMF ESV with two small Fiat ESVs (Fiat 2,000-pound and Fiat 2,500-pound classes) at a closure speed of 75 mph. Preliminary analyses of crash test results are presented in this report. The vehicle-to-vehicle tests were highly successful in that structural integrity of the Fiat passenger compartments was adequately maintained. The AMF vehicle's hydraulic subsystem absorbed a significant portion of the crash energy in its 20-inch stroke, thus offering reduced aggressiveness to the small Fiat vehicles. However, human survival in terms of meeting current occupant injury criteria was not evaluated since dummies were not included in this preliminary test series. Such an evaluation is planned as part of future phases of this ESV evaluation program.

To ensure cost-effectiveness, automotive industry solid-state device requirements, a small percentage of total U.S. consumption, will be met through custom designs using technologies applicable to non-automotive applications as well. N-MOS and complementary-MOS technologies with their cost and performance advantages and smaller size will prevail in digital signal processing; bipolar IC's plus IC's combining bipolar and MOS technologies on the same chip will be used for linear signal processing. Multiple-epitaxial structured silicon power devices will be used as actuator drivers. The reliability/cost equation will be solved by using buffered power sources to permit use of custom-designed low-voltage IC signal-processing circuits. Power devices having device characteristics that can withstand the high voltage transients will provide the interface between the low-level signal processing and actuator drivers.

THE SIXTH FORUM, held in conjunction with TRANSPO 72, was built around the theme “The Air Cargo System -- a Profitable Solution.” This Seventh Forum recognizes that air cargo is, in reality, “coming of age” and that it is timely to define precisely its position in the marketplace; hence, the theme: “Air Distribution -- Maturity in Marketing.” Some of the discussions at the Sixth Forum pertained to containerization, operating costs, rate structures, multi-modal movements, and to transport of cargo by contract and by private carriage. These categories are still applicable to our status today, despite the impact of the energy crisis and the resulting increases in the cost of aviation fuel and other petroleum products. Admittedly, there are a number of areas where there has been little or no progress since the last Forum -- and some of these will be mentioned. Nevertheless, the main thrust of this review will be to focus on the progress made in our industry during this two-year period.

This paper describes the application of composite laminates consisting of bonded rubber and plastic layers to discrete energy absorber units and flexible bumper systems. These laminates are manufactured by the fusion bonding technique applied to injection moulding of discrete EA units and thermoforming of resilient EA bumpers. The two material construction allows greater design flexibility in unit and system design. The properties of the dual material system permit a high ratio of energy absorption per unit weight coupled with full recovery of pre-impact configuration. The performance and installation requirements of the ‘V’ shaped discrete bumper mountings is described in detail. Experimental developments in fully flexible bumpers are then discussed.

Through our development work on a bumper system that would meet the requirements of FMVSS No. 215, “Exterior Protection of Passenger Cars,” the correlation between the physical properties of the compressible solid, and the mechanical structure and load-deflection characteristics of the shock isolator system has been clarified. A number of silicone rubbers were investigated and their molecular weight and cross-linking density changed. The results of these investigations have been applied to the new shock isolator system of our 1974 model vehicles.

A major difficulty in performing cost-benefit analyses of bumper designs is the fact that much of the damage from low-speed crashes is never reported either to public agencies or insurers. Much of this unreported crash damage remains unrepaired, at least for some time after the crash, and thus surveys of unrepaired crash damage can provide one source of data for some of the unreported crash damage. During the summer of 1974, surveys of unrepaired crash damage were conducted in seven metropolitan areas. The results of these surveys are presented. It is concluded that the present state of knowledge on the frequency and amount of unreported crash damage is too limited to enable this essential component to be adequately incorporated into cost-benefit analysis of bumper designs.

Data from the Nationwide Personal Transportation Study (NPTS) and other sources have been used to generate distributions of vehicle miles traveled (VMT), average speed, and fuel consumption as a function of trip length. Approximately one third of all automobile travel in the U.S. is seen to consist of trips no more than ten miles in length. Because short trips involve more frequent stops and a smaller percentage of operation during warmed-up conditions, nearly half of the fuel used by automobiles is consumed during the execution of these short trips. The typical trip of approximately ten miles in length has been shown to result in a fuel economy that is equal to the average fuel economy achieved for all trips combined.

Information about public driving patterns was collected in three ways. 1. Chase Cars, equipped with instrumentation were used to monitor 2,500 randomly selected trips in various parts of the United States. Data relating to 11,000 miles of operation was thereby recorded and analyzed. 2. Long duration strip-chart recorders were installed in vehicles in use by the public. These devices recorded traces of speed vs. time, while the vehicles were in motion. More than 12,000 miles of driving were recorded. 3. Passive electronic recording devices were installed in selected vehicles which were in use by the public. These devices recorded the portion of miles driven within various speed bands. In this manner, more than 61,000 miles have been recorded. This study is still in progress and is intended to monitor long-term trends in customer operation.

A new fuel economy test procedure has been developed for passenger cars and light trucks that is basically similar to the established procedures used by U.S. automobile manufacturers. The new SAE procedure provides a standardized method for use in obtaining and comparing vehicle fuel economy values that relate to average conditions encountered in various modes of driving. The various aspects of the program discussed in the paper include road versus laboratory testing; existing procedures; evaluation, comparison and selection of test cycles; test repeatability amongst facilities; relation of test results to those obtained in actual customer usage; comparison of independent consumer survey results; and correction factor development and application.

A study was conducted to determine the potential reduction in automotive fuel consumption based on the use of innovative systems and improved components. Technological areas investigated were: spark ignited engines with and without turbocharging, electronic feedback controlled fuel injection with duel bed catalytic converters, stratified charge combustion, light weight diesels, lock-up torque converters, continuously variable ratio transmission, tires aerodynamic drag, vehicle weight, engine accessories and optional equipment. Standard and compact-size 1973 model year vehicles were selected for analysis using a computer-simulation program to predict fuel usage and performance with and without incorporation of the improvements. In addition estimates were made as to whether modified vehicles complied with study constraints such as emission, safety, noise and user requirements.

Increasing demands on product performance, coupled with increasing emphasis on product reliability and safety, have made many conventionally-used materials virtually obsolete for automotive under-the-hood service. Celanex thermoplastic polyester, an injection-moldable engineering resin, has found, and is continuing to find application in new high performance automotive ignition components, where it is providing improved properties at reduced costs. This paper reviews the properties and processing characteristics of this unique material as it relates to ignition component requirements, and discusses part design and tool design parameters necessary for obtaining optimum results. A number of ignition components currently in commercial production in glass fiber reinforced Celanex are illustrated, and details are given of some of the testing which preceded the commercial acceptance of the parts.

The stamping of thermoplastic sheet is gaining acceptance in the automobile industry. The process has been used in consumer product areas which are less demanding than automotive, but this has demonstrated process viability. As the process gains in acceptance, special materials are being developed for stamping of components which have properties required for specific applications. There are several variations of the basic process as related to the product, material, and equipment. The definite advantage of stamping is rapid cycle time. In-the-mold decorating and pre-decorated materials will provide further applications in trim components. Stamping of thermoplastic provides an additional tool for automotive engineers.

The adverse effects of charge dilution on combustion of spark ignition engines are well known; as a tool for reduction of nitrogen oxide emission, it becomes important. Some methods of analyzing combustion phenomena in a single-cylinder engine (27.1 CID) with charge dilution were tried. Multiple ionization probes roughly indicate the pattern of flame propagation, but details of the flame, especially charge dilution, cannot be measured by this method. Flame photographs, on the other hand, showed clearly the effects of combustion chamber design on flame propagation and its cyclic dispersion. The effects of combustion chamber configuration, ignition energy and spark duration, ignition timing, composition of diluent gas, air-fuel ratio, and mixture homogeneity were examined. Mass burnt fraction was calculated from both flame photographs and pressure indicator diagrams.

This paper discusses the Mercedes-Benz V-8 engines, their design as compared to US V-8 engines, and development concerning exhaust emission control and fuel consumption. Also covered are special problem areas, and their respective solutions which today have come to be of secondary importance, for example, the lubrication system, defoaming of the lubricant, noises generated by the lubrication system, and the adaptation of the hydraulic valve clearance adjustment to high engine speeds.

Normal means of reducing vehicle fuel consumption, such as lower speeds, shorter trips and proper maintenance, are well known. This paper reviews a number of other, lesser known, fuel conservation measures this paper includes practical recommendations for their application and cites results that may be achieved.

The California Legislature conducted an investigation into the low emission properties of steam-powered automobiles, 1972-74. Two steam propulsion systems were built and installed into sub-compact cars suitable for urban driving. The Aerojet Liquid Rocket Co. installed a steam turbine in a Chevrolet Vega, while Steam Power Systems built a piston engine system for a car of special design. The project demonstrated that it is possible to reduce exhaust emission levels to less then those required by the 1978 Federal standards. Road performance was adequate for urban-suburban driving. Fuel consumption was higher than comparable internal combustion-powered vehicles. Guidelines for future improvements are given.