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Viewing 85291 to 85320 of 86934
1938-01-01
Technical Paper
380118
R. B. Haynes
DEVELOPMENTS in spline and gear cutting discussed in this paper include actual production results in climb-hobbing of splines and experimental results in climb-hobbing of gears. “Climb-hobbing” is defined as that method of hobbing wherein the cutting action starts at the surface of the part being hobbed and ends at the root of the spline or tooth - the direct opposite of the conventional method. Important advantages claimed for the method are a superior finish, increase in hob life, and lower power consumption. Finishing-process developments considered are finish-cutting, burnishing, shaving, and grinding.
1938-01-01
Technical Paper
380116
Louis Johnson
1938-01-01
Technical Paper
380089
L. W. JOHNSON
1938-01-01
Technical Paper
380091
Otto Jabelmann
1938-01-01
Technical Paper
380093
R. P. Lansing, C. I. MacNeil
1938-01-01
Technical Paper
380092
A. E. Lombard
1938-01-01
Technical Paper
380095
Allen C. Staley
1938-01-01
Technical Paper
380096
F. J. Linsenmeyer
1938-01-01
Technical Paper
380098
S. B. SHAW
1938-01-01
Technical Paper
380099
A. T. Colwell
1938-01-01
Technical Paper
380100
C. J. Vogt, F. A. Ryder
1938-01-01
Technical Paper
380101
C. B. Lindsey
1938-01-01
Technical Paper
380135
Earl Bartholomew, Harold Chalk, Benjamin Brewster
INCREASED performance at high speed, which is an important characteristic of cars built during the last few years, has required the use of intake manifolds of considerably greater cross-sectional area which, together with certain other changes in engine design, cause unequal distribution of the less volatile portions of the fuel not vaporized in the manifold. Consequently, the fuel which enters the cylinders varies in composition. If other conditions are equal, the relative knocking tendency of the cylinders is determined by the distribution of antiknock value through the fractions of the fuel and by the air-fuel ratios of the mixtures in the cylinders. Ordinarily the leanest cylinder knocks the most. Fuels rated in the laboratory by conventional methods as having equal antiknock value may differ considerably in road performance because of differences in volatility and distribution of antiknock value through their fractions.
1938-01-01
Technical Paper
380134
Macy O. Teetor
THE elimination of wear of piston-rings and cylinders can be the ultimate goal toward which to strive but, in reaching this Utopia if it can be reached, the most practical road seems to be by way of wear reduction. Many factors indicate the necessity for a “wear-in” period. At some point in service wear-in ceases and “wear-out” starts. As wear-in takes place, performance only improves to a certain point and, from there on, piston-rings and cylinders can be considered as wearing out. The rubbing action of a piston-ring on a cylinder wall breaks particles loose from the surfaces that act as an abrasive. This breakdown of the rubbing surfaces, regenerative because of the abrasive action of the resulting loose material, causes wear. The ease with which the surface of a material will break down and the physical characteristics of the loose particles so produced are indicated to a great extent by structure. The structure of a material is therefore an indication of expected wear.
1938-01-01
Technical Paper
380141
J. Trueman Thompson
PRESENT interest in ways and means of improving the speed at which many slow-moving vehicles climb grades, springs from a real necessity and an honest desire on the part of all agencies concerned to produce a practical solution. The United States Bureau of Public Roads recently has undertaken to develop apparatus and a procedure which may be used to secure a large amount of data on current hill-climbing practice. It is planned that this method will be applied shortly through the agencies of several of the State Highway Planning Surveys. The apparatus and procedure referred to were used during the past summer to secure a limited amount of “trial” data. Both the tests and data are discussed as well as certain plans which are now being formulated to make a special study of both new and used trucks in the dynamometer laboratory of the Motor Transport Division of the Army, and to correlate these data with actual hill-climbing tests.
1938-01-01
Technical Paper
380139
Gerald M. Rassweiler, Lloyd Withrow
THIS paper represents a continuation of the work with the high-speed motion picture camera described before the Semi-Annual Meeting of the Society, June, 1936.1 The experimental observations consist of pictures showing successive positions of the flame at intervals of 2.4 crankshaft deg. during single explosions, and pressure-time records of the same explosions. A method finally is described for sorting out the pressure changes due to combustion from an observed pressure card. When the pressure changes resulting from combustion are summed and put on a percentage basis, it is found that the per cent of pressure rise due to combustion is approximately equal to the per cent of charge burned (by weight) at the corresponding instants in the combustion period.
1938-01-01
Technical Paper
380138
Ernest J. Abbott
GREAT simplification of understanding and unusual results in production often follow new approaches to old problems. When noise problems are stated in terms of the familiar physical units of pressure, velocity, weight, and stiffness, basic ideas are obtained which can be applied directly to practice. In this way, most of the mysteries and the contradictions of noise problems are eliminated. In their elements, noise problems involve only simple physical factors which are understood easily, and which can be measured with available equipment. Similarly, the solutions involve the straightforward application of known and definite engineering principles. Although simple in their elements, most practical noise problems are very complex because of their combinations. Often much ingenuity is required to measure the physical characteristics of the noise which determine the human impressions obtained from it.
1938-01-01
Technical Paper
380145
T. A. Boyd
THIS paper deals with the road-test portion of the extensive efforts made during 1937 by the Cooperative Fuel Research Committee to get as precise a correlation as possible between the laboratory knock ratings of automobile fuels and their corresponding ratings in cars on the road. It is anticipated that the comprehensive results of car tests reported here, taken together with the results of the laboratory rating program reported in the companion paper, will serve as the basis of the continuing studies aimed at developing the best possible correlation between road and laboratory knock ratings. Work similar to that reported here has been conducted concurrently in England by the Institution of Petroleum Technologists, using British cars and fuels. An exchange of information between the British and American groups working on this problem is being made.
1938-01-01
Technical Paper
380144
Alex Taub
VARIATION in engineering practice between European and American motor cars is to be expected. Many of these differences are brought about by local conditions and must be accepted. However, there are practices that vary from the American that do not justify themselves by result or local conditions. The two outstanding are bore wear and carburetion. This paper deals only with the high spots of these two differences.
1938-01-01
Technical Paper
380142
Russell Pyles
METHODS of increasing engine output are discussed, and supercharging is said to involve few difficulties. The location of the blower drive as it affects frequency and gear loading is considered. Bearing-load diagrams are analyzed for a high-speed and a low-speed engine. Tests indicate a negligible increase in piston temperatures. Fuel-consumption curves show fuel economy comparable with that of the normal engine.
1938-01-01
Technical Paper
380149
J. R. MacGregor, W. V. Hanley
FUEL deposition and ring-sticking tests are described which were performed in several single-cylinder and multicylinder service Diesel engines in the laboratory. The development of an accelerated test method is outlined with special reference to the effects of engine variables on deposition. Decrease in load, speed, or jacket temperature or increase in altitude were found to increase fuel deposition. Increase in running time increased the exhaust deposits linearly but, within the combustion-chamber, equilibrium deposition was reached in a few hours of operation. Marked differences were found among fuels in the single-cylinder test engine after 24 hr. of operation under the accelerated conditions. Fuels doped with different types of cetane-number improvers indicated that ignition quality is a factor in fuel deposition under certain operating conditions in some engines.
1938-01-01
Technical Paper
380147
L. W. Child
ALL factors necessary for year-around air conditioning of cars and buses are covered generally in this paper. How the desired results were obtained in both winter and summer air conditioning is explained with the aid of a chart of air requirements. Types of equipment are discussed, especially the refrigerating system, giving powers, capacities, and safety factors.
1938-01-01
Technical Paper
380148
A. S. Van Halteren
MODERN developments in the automobile industry have created a paradox. On the one hand, increased speeds have placed greater demands on the brakes whereas, on the other hand, the trend toward streamlining has greatly handicapped brake performance. As a result brake drum and wheel diameters have been reduced and the flow of air to the brakes has been restricted by shrouding them with wheels and skirted fenders. In the solution of brake heat-transmission problems, the subject is considered under the following headings: the amount of heat generated; the manner and rate of heat flow into the brake; and the manner and rate of heat flow out of the brake. Heat-transmission calculations of specific examples are made that indicate the amount of heat dissipated by conduction, radiation, and convection.
1938-01-01
Technical Paper
380121
C. H. Baxley, T. B. Rendel
FOLLOWING the adoption of a suitable design of engine and a tentative procedure for operating this engine, the work of the Volunteer Group has covered the investigation of other methods of measuring cetane number of Diesel fuels looking towards a simplification and improvement of reproducibility of the procedure. Results of a second series of cooperative tests are given, using the procedure adopted in the Group's last report together with a series of tests on the same fuel using the critical-compression-ratio method with an interval timing-control device. Results of the first series do not show such good agreement, the grand average deviation on twelve samples being of the order of ±1.9. Results of the critical-compression-ratio tests show improved agreement due to better standardization. Tests on three alternative methods based on the delay method, but using different instruments for recording the delay, are given. Results on two different full-scale engines also are presented.
1938-01-01
Technical Paper
380117
H. W. Prentis
1938-01-01
Technical Paper
380125
A. E. Becker
THIS paper is a progress report of the Cooperative Fuel Research Committee, dealing with the laboratory section of the study of the knock-rating correlation problem. It is proposed that these results and those obtained on the road be the basis for further study aimed at the development of better correlation between road and laboratory ratings.
1938-01-01
Technical Paper
380128
W. J. Cumming
1938-01-01
Technical Paper
380126
D. A. Wallace