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Present techniques for classification and analysis of surface roughness are based on a trace of surface profile, or a measure of arithmetic mean, or rms value of the profile height, but this information is not adequate, and a new technique has been developed to classify surface roughness based on frequency content of the variance of the surface profile. A digital computer frequency filter has been devised to allow differentiation between roughness height and waviness or general surface contour. Three representative surfaces have been measured and classified according to this analysis and data are presented in support for roughness classification techniques.

The requirements for cylinder pressure measurement for mechanical load, imep, and cycle analysis are developed. Methods for determining errors in transducers are presented, and the results are shown. The tests include passage error, hysteresis, nonlinearity, mounting strains, thermal strain, and twist in the crankshaft. Theories are developed to predict errors due to time or phase delay, passage, and thermal strain. The theory of the balanced pressure indicator is developed and the minimum delay and pressure error are calculated. Read-out systems are evaluated. Areas needing improvement are pointed out and specifications for the ideal pressure transducer are presented.

The ignition delay in diesel combustion has been studied in a turbulent chamber engine. The criteria used to define the end of this period are the pressure rise and illumination due to combustion. The pressure rise delay is generally shorter and more reproducible than the illumination delay. The effect of the following factors on the ignition delay were studied: cylinder pressure, fuel/air ratio, fuel injection pressure, cooling water temperature, and engine speed. Data concerning the effect of cylinder pressure on the pressure rise delay period, at constant air temperature, were correlated and compared with previous experimental results. The analysis indicated that the pressure rise delay is affected by physical and chemical factors as well as thermodynamic parameters that control the several forms of energy during the delay period.

A theoretical stress analysis was performed on the crankshaft of a 2-cyl engine using routine engineering calculations, and the results were verified by test. Agreement was satisfactory under controlled operating conditions. Actual service loads were found to be about half as high as the maximum possible. The fatigue strength of production crankshafts was measured in a specially built fixture. About 20-30% improvement in fatigue strength could be achieved by shot peening or Tufftride.

Steps taken to improve fatigue life of connecting rods in small high performance 2-stroke cycle engines are outlined. Design and surface treatments to improve the life of conrod bolts are covered, and the design of the cracked joint for minimum stress in the bolts is derived. Optimum case-core ratio at the conrod joint for maximum strength and good break characteristics is worked out. The hazards of rough spot face surfaces, out-of-square bolts, tight threads, insufficient or too much initial bolt tightening torque are shown. The inadequacy of shot peening in some cases and metallurgical and forging defects are also discussed.

A range of 60 deg V-4 and V-6 engines with four displacements has been developed by Ford of Britain for varying vehicle application. Some of the features which make these units unique from previous light car engine design include bowl-in-piston combustion chamber cross-flow cylinder heads, individually mounted rocker arms, fixed piston pins, deep skirted cylinder block, closed crankcase ventilation system, throwaway lubricating oil filter, primary balance shaft (on the 4-cylinder version), high efficiency centrifugal type water pump, water heated intake manifolds and water temperature controlled automatic chokes. An important objective of the development and testing program, namely, minimum need for servicing and attention to parts, was also achieved.

A simplified analysis is made of the directional stability of vehicle combinations, such as a tractor combined with one or two semitrailers or a truck and full trailer. Vehicle combinations are treated as linear dynamic systems with two degrees-of-freedom for each unit. The equations of motion are derived considering the influence of braking and acceleration, and a characteristic equation for traveling at constant speed is obtained. The Routh criteria are examined to distinguish between stability and instability, considering oscillatory and aperiodic motions separately. Special attention is given to the behavior of the vehicle during braking, with discussion of the influence of various design parameters and the distribution of the braking forces applied to the wheels. Finally, a new design of fifth wheel device is presented in order to stabilize tractor-semitrailer combinations.

Plastisol technology with respect to its use in automotive interior trim parts is briefly reviewed. Manufacturing processes are discussed and specific parts in 1968 production are listed.

This paper reviews the state-of-the-art with respect to compression and oil control ring designs used in 1967 model engines. Specific precautions with regard to details in piston ring specifications for optimum oil control and blowby performance are discussed. For 1967 engines, barrel face piston rings, molybdenum piston ring facings, and smoother cylinder bores are being used for improved oil economy and wear performance. New developments in piston ring coatings and materials are reviewed.

To reduce the losses incurred in motor vehicle operations, all of the factors contributing to the creation of the accident event must be considered. A systematic itemization of these factors indicates that perhaps several hundred environmental, vehicle, and driver factors affect traffic safety. In order to identify the changes which must be made in the interests of improved traffic safety, the techniques of systems analysis can be applied to select those programs which will provide the greatest improvement in traffic safety for the effort expended, whether it be in the area of vehicle improvements, roadway improvements, or driver improvements.

Traffic safety is described as a problem with technological, behavioral, sociological, and value dimensions. Accidents are viewed as “localized system failures,” symptomatic of an underlying problem that includes: an imbalance between driver capabilities and the demands of the motor vehicle transportation system; the absence of functional communication between the administrative units responsible for the input and functioning of men, vehicles, and environment; and the lack of recognition and resolution of the trade-offs between safety and other desired system outputs and characteristics.

The effectiveness of extended plug nozzles in reducing jet engine exhaust noise was investigated on small scale laboratory nozzles at ITT Research Institute and on a small turbojet engine at Williams Research Corp. The geometry of the nozzle was optimized on the basis of noise reduction versus thrust loss. The extended plug reduced noise on both laboratory nozzles and the turbojet engine for pressure ratios above critical. The use of a small turbojet engine for evaluating noise suppression devices is described.

A portable X-ray diffraction system was used to measure strain in 7039-T6, 6061-T6, and 2014-T6 aluminum alloy sheet stock, with X-ray elastic constants determined for these alloys. Residual stress estimates have been made as a contribution to the failure analysis of cracking in production parts. The procedure used to make the stress estimates involves surface preparation by electropolishing, the preparation of three focused, back reflection photographs, data collection by microphotometer, and interpretation of the data by the “sin2 Ψ method.” A computer program has been written to calculate the slope of the line, Δd/d0 versus sin2 Ψ, from the positions of the lines on the films. The crystalline structure of 2014-T6 aluminum alloy sheet stock is such that a large specimen sampling is required to obtain suitable strain measurements.

The advent of the on-board gas turbine auxiliary power unit in commercial aircraft created problems of excessive noise levels affecting both passengers and aircraft personnel. This paper analyzes those problems and outlines the advanced techniques being used to reduce gas turbine noises to an acceptable level. Being directed primarily at the gas turbine engineer, a brief explanation of pertinent acoustical terminology is presented to provide a basis for his understanding. Treatment of the major noise sources of a gas turbine and its installation are discussed and evaluated from the standpoint of maximum noise reduction.

This paper contains a practical discussion of the applications of reverberation chambers to acoustical measurement problems often encountered by noise control engineers. The important characteristics of a reverberation chamber are explained and typical reverberation chamber construction demonstrated. The advantage of the reverberation chamber as a simple method of measuring certain acoustic phenomena and acoustical properties is illustrated by its application in three typical examples. First, the application of the room to measurements involving directional sound sources is illustrated by a study of automotive alternator noise. Second, the use of the room as a nondirectional sound source in measurement of acoustical material properties is illustrated by sound barrier tests of material sample installations.

Investigation of cracked rotor “D” spar revealed an area of tensile residual stress in the area of the failure origin. Normal rotor spar processing results in the formation of compressive residual. The service history of the cracked spar indicated that it had been buckled, and that compressive yielding had occurred. This resulted in a “wiping out” of the compressive residual stress, and the subsequent formation of a tensile residual stress. Laboratory tests aimed at reproducing the buckle proved successful and full scale fatigue tests of the buckled spars resulted in failures significantly below the normal test scatter. Inspection criteria, based on X-ray diffraction residual stress analysis, have been instituted.

In this paper the question, “How can industry rapidly and effectively utilize government-sponsored technology?” is surveyed. The author thinks that, since both the interrelations between government, universities, and industry in the creation of technology and the general economic climate have changed, industry itself must accept the challenge of using technology developed for government projects. There are several pertinent issues: market applicability, management attitudes, personnel motivations, investment protection, and the necessity to establish a strong barrier against government intrusion into areas properly the province of private industry.