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An accurate, compact, and convenient instrumentation system for vehicle brake testing has been developed. The system comprises a counter assembly mounted inside the vehicle, a switch that closes at the onset of braking, and a specially modified “fifth wheel.” Stopping distance and initial vehicle speed are displayed in numerical form on the face of the counter assembly. Data acquisition is accomplished almost entirely by digital techniques. Measurement accuracy is therefore enhanced (by eliminating the usual dependence on analog voltage scaling). Digital techniques also permit useful control (decision-making) functions to be included. Once such function is the unique feature of automatically eliminating erroneous distance pickup during vehicle “rock-back” at the end of a high deceleration stop.

Powerful capabilities for use in the analysis of complex automotive systems have recently been developed. These capabilities bring the newly developed electronic testing equipment together with the powerful computational techniques to perform a total system dynamic design analysis. The analysis tool developed is called the building block approach, whereby complex system behavior is defined by analyzing and combining the dynamic behavior of simpler components and subassemblies. The dynamic behavior of each component is obtained from a separate analytical investigation or from a specific type of experimental test procedure. Component data are then combined mathematically to predict dynamic behavior of the full system under the prescribed loading conditions. With the system simulation completed, design changes in any or all components can be evaluated. The effect of changes in any component on the operating behavior, vibration, noise, and stress can be ascertained.

This paper consists of three parts. The first part discusses good and bad electrical wiring, its causes and effects, and the ways in which specific hindrances to good performance can be minimized or eliminated. Several examples are cited to pinpoint practices that create problems in the wiring system and to show how such problems can be avoided. The second part covers vehicular lighting systems: malfunction and causes of failure, and ways of protecting the lighting system. Also discussed are the efforts of the industry associations to provide quality and standardization. The final section tabulates the results of data which have been entered into a computer memory bank in regard to the cost of maintenance on the lighting system.

The high level of reliability required of safety-related automotive parts, such as brake control system components, demands thorough functional testing of the component. A highly automated test system now in use at a component manufacturing plant helps to provide this reliability by performing 12 separate tests on each brake combination valve produced. The air test and the 11 hydraulic tests are described, features of test system design and operation are discussed, and the test equipment used is listed.

This paper gives insight into comments and suggestions gleaned from computerized maintenance reports pertaining to the cranking system. Part I deals with the starting system: what makes it expensive to maintain and what can be done to reduce maintenance costs. Specific suggestions are listed. Inasmuch as 90% of the overall maintenance costs of the cranking system is brought about by faulty batteries, it is important to analyze the nature and extent of battery troubles. This aspect of the cranking sustem is discussed in Part II, including tests made of 10 Ryder trucks to delineate problem-causing practices and design deficiencies that contribute to high maintenance costs. Part III covers the importance of battery cables and connections. Major items of cranking system expense are compared to show that possible savings can result from improved cables and connections.

Engine after-run, sometimes referred to as “run-on” or “dieseling,” has existed for many years, but seems to be occurring more frequently with late-model cars and low-octane gasolines. A vehicle study was conducted to gain a better understanding of the factors that influence after-run. Engine operating variables, such as high idle speed, lean idle mixture, and retarded basic spark timing, all increased after-run frequency by increasing the throttle opening (intake charge density). Reduced Research-octane number of the gasoline also increased after-run frequency, but Motor-octane number and hydrocarbon composition did not have any effect. After-run exhaust contained about 125 times more aldehydes than engine idle exhaust, and it caused eye irritation and an obnoxious odor. Compression ignition, rather than surface ignition, is most likely the cause of after-run.

This paper discusses the use of data processing to pinpoint the causes of component failure and thereby help maintenance supervisors do a more accurate job of determining component durability and cost, and in writing truck/trailer specifications. Results of on-the-spot evaluation of alternator failures on 206 trucks are analyzed. Also listed are several design deficiencies that must be corrected at O.E.M. level to extend alternator life.

This paper outlines reasons for emission legislation in Europe, makes comparisons with the United States where appropriate, and describes the pace and extent of existing and proposed legislation. It draws attention to variations that exist within the European continent due to national influences. The effect of legislation on the plans of the automotive and petroleum industries is discussed, and the effect of low-lead and unleaded fuel on performance of both existing and projected engines is considered. An attempt is made to assess the effect of all influences on the North American and European automotive industries and to forecast the general trend in automotive and fuel related developments in Europe over the next 10 years.

Motorists who use lead-free rather than leaded gasolines postpone the need to replace spark plugs, exhaust systems, and carburetors, and thus save a significant part of their maintenance dollar. These savings were documented in a four-year test with a fleet of automobiles operated in city-suburban driving, and in a five-year survey of a representative sample of the motoring public. Savings on gasoline-related maintenance over the lifetime of an average car were about $0.05/gal in the fleet tests and $0.04/gal in the survey. 2

Time-temperature histories of fuel system components were measured on 80 passenger cars in the summer of 1968 in Los Angeles for several 24 h use patterns simulating normal vehicle operation. These included both driving segments on several types of highways and engine-off soak periods. Ambient temperature, type of driving, and vehicle design features have the greatest influences on fuel system temperatures. These time-temperature histories are of interest for fuel system evaporative emissions study. Two applications of these data have been reported.

Problems of fuel maldistribution have been accentuated in late-model cars which use lean carburetion to reduce emissions. This condition has resulted in increased drivability problems, such as hesitation and surge, as well as producing losses in power and fuel economy. Fuel distribution can be improved by gasoline additives which form a coating of low surface energy in the induction system. As a result of improved distribution, benefits were observed for many cars in drivability, fuel economy, and exhaust emissions.

Computer analysis and large-scale model experiments to determine the air side performance of louvered fin evaporator cores are discussed. Heat transfer and pressure drop are determined for several configurations and compared with calculated values. The experimental setup and digital computer program used for both experiments are described. Effects of condensation, fins per inch, fin thickness, and other core characteristics are determined. The computer model for heat transfer rate appears valid over a Reynolds number of at least 10. Two empirical parameters of the program, one on the liquid side and one on the air side, should be adjusted after comparison with highly accurate empirical data. Additional work is needed to improve the accuracy of data from the large-scale models, although determination of relative performance of different cores appears to be a present capability.

The ROVAC unit is a rotary vane combination compressor-expander-circulator, which is the key element in a new air-cycle refrigeration system. Results of an analytical and experimental feasibility study of the system are reported here. The objective of the study was to develop and verify a mathematical model of the system, including heat-exchanger pressure loss and mechanical friction. A parametric study was made to determine the geometry for a unit capable of cooling a passenger car, and a conservatively designed prototype was built and tested. The prototype system produced a cooling capacity of 5400 Btu/h and generally verified the accuracy of the mathematical model. The coefficient of performance of the prototype system is somewhat lower than that of a typical vapor-cycle system.* However, the ROVAC system is much simpler and will most likely be cheaper to build.

This paper presents a simulation model to predict the thermal performance of automotive air-conditioning condensers. Operation of the air-conditioning system and the function of the condenser are discussed briefly. Details of the formulation to calculate various performance characteristics are given. Potential applications of the corresponding computer program are described. Comparison of the computer results to test data shows that the model predicts heat rejections within 3-7% and air discharge temperatures within 0.5 F of the laboratory test data.

The basic theory and the techniques upon which the Air Conditioning Analytical Simulation Package (A/CASP) computer program system was developed is outlined. Methods for simulating car air conditioning components, systems, and cool-down performance by computerized mathematical models are presented. Solution techniques for the models of the evaporator, condenser, compressor, and vehicle are outlined. The correlation of test data and analytical predictions is demonstrated.

The university, in training engineers to meet the changing needs of society, must be more aggressive than in the past in anticipating changes before they occur and in performing research to determine whether anticipated changes are real or a passing fad. The professional societies must serve as the vehicle through which the university can work with government and employers of engineers to determine the present and future needs of society and to achieve a balance in quality and quantity of engineers and scientists to meet these needs. The United States, in the recent past, has almost had a monopoly among the nations of the world in advancing technology. But as other countries approach us, and in some cases exceed our capabilities, we must muster all our resources to have the kind of engineer and scientist that can compete with this very drastic change.

In developing the AMF Experimental Safety Vehicle, two of the major problems encountered involved limitation of passenger compartment intrusion during side impacts, and dissipation of vehicle kinetic energy during high-velocity front and rear impacts. A design solution to the first of these problems has been developed, which has as its basic element an aluminum honeycomb sandwich door panel. Several evolutionary models have been built and tested under both static and dynamic loading, including full-scale vehicle crashes. Actual behavior has agreed very well with analytically predicted behavior, enabling the side structure system to meet ESV design goals. The solution developed for the second problem utilizes variable stroke hydraulic buffers to absorb the required energy. Bumper systems incorporating such buffers were tested successfully in various impact configurations at velocities of up to 50 mph.

The shock response spectrum is defined and applied to several areas of automotive design and crash test evaluation. An examination of the shock response spectra for several deceleration pulse shapes for vehicle front structure design indicates that there is no “best” input pulse applicable to all occupant/restraint systems. However, in the 8-12 Hz frequency range of current occupant/restraint systems, the square wave does appear to offer significant reduction in peak deceleration response for the fully-restrained occupant. The shock response spectrum method is also used to compare a velocity-sensitive versus constant-force front structure, deceleration data from different vehicles, and accelerometer data having different frequency limits. These examples illustrate that the shock response spectrum can be a useful tool for evaluating particular automotive crash data and for comparing the relative potential damage of deceleration pulses associated with different vehicle designs.

The development of chassis components to satisfy both formal vehicle response specifications and practical requirements of acceptable passenger car performance was undertaken as a part of the Federal Experimental Safety Vehicle program. Since the formal specifications were new and had never been applied to passenger car chassis design, the necessary development effort was challenging and explored new areas of vehicle performance optimization. The chassis configuration resulting from development for these new standards offers dramatic gains in several response and adhesion qualities, while retaining reasonable ride comfort.

Many of the formal system engineering procedures and techniques developed in the aerospace industry have convenient informal application to the analysis, evaluation, and qualification of new automotive design. This paper describes such “systemization” from a product engineering viewpoint in the development of a hardtop window project. The project is traced through its several design and development stages; and the advantages of the system engineering approach, as well as some of the problems encountered, are explored. The paper concludes with a discussion of additional controls that would have been required to yield the full information recording/retrieval capability demanded for complete system integration on larger projects. THE COMPLEXITY OF the present-day automobile is as evident in its door window systems as it is beneath the hood.