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Presented in this paper is a brief review of momentum exchange theory for Jet Noise Suppression. “Experimental Results from Scale Model Tests” are included. These data exhibit peak to peak attenuation of 20 db along maximum exhaust noise azimuths at a nozzle pressure ratio of 3.1.

This paper presents the results of an investigation cooperatively undertaken by Esso Research and Engineering Company and Ethyl Corporation to determine whether the hydrocarbon-type effect observed in road antiknock studies of gasolines is independent of other fuel properties over and above laboratory octane numbers. For this study, 51 finished gasolines were carefully blended from 57 base stock components to provide controlled levels of those major fuel properties which affect road performance. The controlled properties were Research octane number, sensitivity (RON minus MON), ratio of aromatics to olefins, tetraethyllead content, octane-number distribution in the fuel's boiling range, boiling-range location of the unsaturated hydrocarbons, and sulfur content. A unique feature of the blending scheme was the formulation of blend pairs, in which all but one of the major fuel properties were essentially equal.

HIGH-ENERGY particle accelerators are among the most important, most complex, and most expensive research tools now used in scientific research. This paper presents a summary of the subject to date. To accelerate atomic particles to energies of billions of volts, it is necessary to provide some means whereby the particles can be given successive kicks in energy — the total of the energy received in all of these kicks adding up to the desired final energy. Such high-energy accelerators can be classified into two categories: linear and circular. The author discusses the advantages and disadvantages of both.*

THIS PAPER describes how radiotracers were used to determine the effect of certain oil variables on wear in marine diesel engines. The tests were made with a clean engine oil system and with abrasive contaminant added, to show how filtration, oil detergency level, and abrasive particle size affected piston-ring wear. The author concludes that detergent-type oils used in a relatively clean engine will effectively minimize piston-ring wear. Filters are necessary to protect diesel engines from gross quantities of wear debris produced as a result of dirty engine operating environments. For operations that require protection of moving parts against abrasive materials, the use of full-flow filters in the lub oil system is recommended. When essentially clean conditions prevail and when using low detergent level oils, bypass filters might be more beneficial in controlling wear rates.*

In 1957 Chrysler Defense Engineering began the development of an aerial jeep vehicle. Within security limitations, this paper discusses the progress made thus far on the project. The aerial jeep is essentially a hovering and low speed vehicle. No means have been provided for propelling it on the ground. The role or mission of the vehicle with respect to helicopters and ground vehicles is explained. Its application initially will be military, but the implication for civilian use seems obvious. While the Chrysler aerial jeep may outwardly resemble others currently under development, the similarity is only superficial. Two features make this vehicle unique in its class: the application of a rigid, fixed-pitch propeller and the use of simple vanes as a means of control. Problems involved in the development of a workable vehicle configuration are described, together with research work for their solution.

COMPARISON of work capacity per unit mass and volume of different energy carriers shows that liquid hydrocarbons are superior to other energy sources. Solar and nuclear powerplants as well as their use in conjunction with a steam engine are examined in this paper. Suitability of an electric drive is discussed. Using a production 2-stroke diesel engine and its development forecast, a comparison is made of spark ignition, diesel, and gas turbine engines. The status of the free-piston engine turbine combination is reviewed.

INDOOR CLIMATIC testing provides a 24-hr-a-day means for continuing developmental work on engine cooling, car heating, and air conditioning throughout the year. This paper describes one such test facility at General Motors. The authors discuss engine cooling, including a description of the hot-tunnel test facilities, test procedures, and a comparison of results with actual road tests. In the second part of the paper, they treat the development of air-conditioning systems, describing the simulation of outdoor conditions and correlation with road tests.

TODAY'S high-compression engines present new problems of engine noise to automotive engineers. This paper deals with some of the factors which contribute to rumble, knock, and surface ignition. The work was primarily concerned with the influence of fuel composition on the equilibrium octane number requirement and surface ignition tendency of high-compression engines. Both the effect of the combustion-chamber deposits formed by the fuel and the effect of the combustion characteristics of the fuel itself were considered. The results indicate that a reduction in gasoline tail-end volatility or the use of an effective ignition control additive can reduce knock, surface ignition, and rumble; while use of gasolines containing high concentrations of aromatic hydrocarbons can increase these combustion difficulties.

In laboratory engines instrumented to measure surface ignition, vibration and noise; various types of surface ignition, even non-knocking, caused obvious roughness. Additives effective in controlling surface ignition were helpful in reducing vibration and noise. However, in clean engines, pure hydrocarbons with normally high combustion rates resulted in obvious harshness and roughness. These effects, comparable to surface ignition, indicated the margin between normal and abnormal manifestations may be quite narrow. A severe and increasingly common occurrence with test engines has been shorting of spark plug gaps by grossly migrating light duty deposits under moderate to heavy stress.

The development of a catalytic converter system for oxidizing exhaust hydrocarbons is presented. Also presented are possible solutions to several mechanical problems associated with catalytic converters such as introduction of secondary air, excessive exhaust system back pressure, attrition loss of catalyst material, and exhaust system noise. Data are presented on the efficiency of vanadium pentoxide catalyst in the Ford catalytic converter system. Overall operating efficiencies of 6-3% can be expected in the removal of exhaust hydrocarbons. During tests with the converter in a smog chamber, average hydrocarbon conversion efficiencies of 88 and 91% respectively were achieved for idle and deceleration, and efficiencies of 68 and 74% respectively were achieved for acceleration and cruise.

Using the technique of substituting electrical parts which had been in service for those on an essentially new 1958 automobile, the paper shows a substantial radiation in hydrocarbon emissions possible as a result of the maintenance condition of these parts. The wide range of emissions which results from modification of the idle adjustment is also shown. The 1956 CRC Field Survey data are examined on the basis of these findings and the conclusion is reached that the high concentrations reported are probably in the right order of magnitude. By comparing Field Survey data with those from a regularly maintained Service Fleet it is concluded that substantial reduction in hydrocarbon emissions is possible through regular maintenance. It is also concluded that a fuel saving may accompany this reduction.

EARLY in 1955 the Automobile Manufacturers Association created the Induction system Task Group to build, test, and evaluate devices for the reduction of unburned hydrocarbon emission from vehicles by induction system methods. This paper is a progress report of the work performed to mid-1957 by the group. Two types of devices are described: those which stop the flow of fuel from the carburetor during the deceleration cycle and those which maintain burnable mixtures during deceleration. However, the effectiveness of such devices is limited. Los Angeles traffic survey data have indicated that the hydrocarbon emission during deceleration is considerably less than reported by early investigators and that relatively low speed decelerations predominate in traffic. In addition, the wide variety of carburetors and engine installations in use today make it unlikely that any one device is entirely suitable for universal adaptation.

AN IMPORTANT effect of combustion-chamber deposits is their tendency to raise the engine's need for higher octane fuels; also, they may cause uncontrolled ignition of the fuel-air mixture and misfiring of spark plugs. This paper describes a new approach to this problem. By means of radioactive hydrocarbons, present in tracer amounts, the authors have been able to conclude the following about the effect of gasoline hydrocarbon composition on deposit formation in the combustion chamber: 1. The deposit-forming tendency of hydrocarbons goes up strongly with increasing boiling point. 2. Aromatics are considerably worse deposit formers than paraffins. Olefins are intermediate. 3. The carbonaceous part of combustion-chamber deposits appears to form via a mechanism involving condensation followed by carbonization. 4. Careful control of the back-end is needed to make a clean-burning gasoline.

Studies have been carried out to determine the extent of damage to petroleum and synthetic lubricants resulting from the exposure to various types of nuclear radiation. Means to reduce this damage have also been studied. Three types of exposures have been used, namely, high energy electrons from a Van de Graaff Accelerator, gamma photons from Cobalt 60 and mixed neutrons and gamma particles from a nuclear reactor. Results indicate that radiation damage to lubricating oil base stocks and finished products involves viscosity change, loss of oxidation stability and development of corrosive tendencies. To evaluate lubricants for nuclear reactor systems, preliminary work indicates that static radiation is a useful technique. However, on an equal energy absorbed basis, there appear to be some differences in product damage caused by electrons and gamma rays and indirectly by neutrons.

For the design of a given free-piston engine, each process must be analyzed with respect to the functioning of the engine. This thermodynamic analysis must then be augmented with a dynamic study of piston motion. The purpose of the research described in this article was to formulate a general analysis of the free-piston engine process which would realistically simulate an operating engine. The analysis was made in terms of variables which allowed the basic engine size and configuration to be selected and the operating conditions for the hypothesized engine to be arbitrarily fixed. For these conditions, a solution from the analysis gives a numerical description of the performance that may be expected of the engine.