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Technical Paper

THE MODERN MOTOR RAIL-CAR

1924-01-01
240024
Because of tremendous demand for mass transportation over long distances in this Country, railroad equipment has become less and less suited for small transportation needs; but a large amount of small-unit transportation exists which can earn a profit for the railroads if they have the equipment best suited to handle it. Gasoline-propelled rail-cars have demonstrated their ability to meet the needs of this small-unit traffic. Types of such rail-cars now operating range from 25-passenger or 10 tons of freight capacity to 60-passenger or 30 tons of freight capacity; in certain services, their capacity can be increased by using trailers and by running them in trains operated by one driver at the front end, who has them under multiple-unit control, at speeds up to 50 m.p.h. and for from 20 to 50 cents per car-mile.
Technical Paper

SAND-CAST ALUMINUM-COPPER-NICKEL-MAGNESIUM ALLOY1

1924-01-01
240021
The importance of the development of a light alloy for use in parts that are subjected to elevated temperatures has already been emphasized in many papers, among which that by S. D. Heron on Air-Cooled Cylinder Design and Development4 should be particularly mentioned. It was with this purpose in view that the foundry of the Engineering Division of the Air Service at McCook Field undertook a brief survey of the alloying, the casting, the heat-treatment, the physical properties and the metallography of an aluminum-copper-nickel-magnesium alloy of the Magnalite type as sand-cast under ordinary foundry conditions. It was found that the alloying involved no particular difficulty. The casting, however, showed the necessity for proper pouring temperatures, gating and placing of the chills and the risers. Several photographs are shown illustrating satisfactory and unsatisfactory methods of molding pistons and air-cooled cylinder-heads.
Technical Paper

WOOD FOR AUTOMOBILE BODIES1

1924-01-01
240022
Shortage of the most desirable kinds of wood for automobile-body purposes has necessitated the substitution of second-choice woods having the essential required properties and the buying of stock for body parts in cut-up dimensions that conform in size with those now produced in the cutting-room. An investigation by the United States Forest Products Laboratory as to the species, kinds, grades, sizes and amounts used by the automotive industry shows that maple and elm comprise over one-half the total amount used and that ash and gum constitute one-half of the remainder. Although the quantity of ash used has not decreased, the increase in the production of medium and low-priced cars in the last few years bas caused a proportional increase in the demand for maple and elm.
Technical Paper

IDEAL AND COMMERCIAL CARBURETER CHARACTERISTICS

1924-01-01
240007
Since previous papers by the author on this subject have dealt with the engine mixture-requirements at some length and these requirements are available to the public, only general information is included in the first part of this paper to illustrate the ideal carbureter-mixture requirements when using a fully developed acceleration device. In the second part, computed data illustrate the car carburetion-requirements of various cars for level-road operation. The car-test data were procured from various sources and combined with research results obtained in the Purdue University Engineering Experiment Station to delineate the factors desired. The results show the information regarding the advisability of using straight-line mixtures. The third part constitutes the main section of the paper, and especial attention is called to it.
Technical Paper

INTAKE-MANIFOLD DISTRIBUTION

1924-01-01
240005
Definite knowledge as to the behavior of gases and liquids in the manifold of an internal-combustion engine being lacking, an attempt is made to answer the questions: (a) How bad is the distribution, (b) how do the different types of manifold compare, (c) why is the liquid distribution in some manifolds poor and (d) how shall we proceed to correct the trouble? The solution of the problem is affected by the facts that, in extremely cold weather, nearly all fuel is delivered to the engine, at the time of starting, as a liquid; that all cars perform poorly under such conditions, some engines, when cold, “hitting” on only one or two cylinders; and that, because of inferior distribution, many multi-cylinder engines are outperformed by single-cylinder engines of similar design.
Technical Paper

ESSENTIALS OF A SUCCESSFUL CONSTANT-COMPRESSION ENGINE1

1924-01-01
240008
The efficiency of internal-combustion engines increases with the pressure of the charge at the time of ignition. Therefore, a compression at full load just below that of premature ignition is ordinarily maintained. But when such an engine is controlled by throttling, the efficiency drops as the compression is reduced, and as automobile engines use less than one-quarter of their available power the greater part of the time, the fuel consumption is necessarily high for the horsepower output. On account, also, of the rarefaction due to throttling, more power must be developed than is necessary to drive the car; automobile engines in which the fuel is introduced during the induction stroke, would be more efficient, therefore, if the maximum compression were constant during all ranges of load.
Technical Paper

ECONOMIC MOTOR-FUEL VOLATILITY

1924-01-01
240006
Reporting on the progress of the fuel investigation now being conducted by the Bureau of Standards, and covering the last of the work that was done under the direct supervision of the late Stephen M. Lee, the author gives the results obtained from the acceleration tests that were made on the road and in the laboratory. Tests relative to starting conditions, as called for by the program, have yet to be made; they have been delayed by the wreckage of the laboratory set-up caused by the explosion of Sept. 20, 1923. Primarily, the tests described here were conducted (a) to determine whether the rates of acceleration obtainable at any given temperature are different for the fuels compared, and (b) whether, when carbureter settings are such as to give the maximum acceleration with each fuel, the fuel consumption under constant speed and load conditions will be greater with one fuel than with the other. Two specific conclusions are stated. W. S.
Technical Paper

PRACTICAL METHODS OF ENGINE-BALANCING 1

1924-01-01
240011
Remarking upon the progress made by the builders of machine-tools in providing equipment for locating and correcting the unbalance of rotating parts, the author divides into three major groups the units of a motor car that require particular attention and treatment to assure a smooth-running mechanism and gives details of the actual methods employed by the company he represents to balance the parts that constitute each group in the vehicles it produces. Representatives of the engineering and the manufacturing departments of this company studied the subject intensively and determined the types of balancing-machine and the methods to be employed, and special balancing equipment was devised also. Details of the balancing practice for crankshafts, flywheels, connecting-rods, clutches and propeller-shafts are presented and the subjects of impulse balance and the maintenance of balance for assemblies of parts are discussed.
Technical Paper

PRACTICAL BALANCING OF A V-TYPE ENGINE CRANKSHAFT1

1924-01-01
240012
Supplementing a paper by another author that treats of the theoretical balancing of this engine, Mr. Anderson presents the practical methods that have been devised to accomplish the results desired. Since this crankshaft is not in running or in dynamic balance without its piston and its connecting-rod assemblies, it is necessary to apply equivalent weights on each of the crankpins when balancing it on a dynamic balancing-machine, and details are given of how these weights are determined. The selection of parts to obtain equal weights is also necessary; a description is given of how this is made. A combination static and dynamic balancing-machine that can be set for either operation is used for balancing the crankshaft. Details of its operation are presented. Service conditions to secure parts replacements within the weight limits specified are outlined, and flywheel, universal-joint assembly and other unit balancing is discussed. The method of testing the completed work is stated.
Technical Paper

MECHANICAL FRICTION AS AFFECTED BY THE LUBRICANT

1924-01-01
240009
Very few data seem to be available on the frictional losses in automobile engines caused by the failure of the oil to perform its function as a lubricant. The researches of the Lubrication Inquiry Committee in England indicate that the friction of a flooded bearing is proportional to the speed of the engine, the area of the bearing and the viscosity of the lubricant and is independent of the pressure and of the materials of which the opposing surfaces are composed. The principal sources of friction in an engine are the crankshaft, the camshaft and the connecting-rod bearings, which rotate; the pistons and the valves, which slide; and the auxiliaries, such as the generator, the pump and the distributor.
Technical Paper

PRACTICAL BALANCING OF ENGINE COMPONENTS

1924-01-01
240010
References to previous theoretical discussions of engine balance are cited prior to consideration of vibrations in four, six or eight-cylinder engines that may either be felt or heard in the car and result from lack of balance. Dynamic arrangement of the engine, unequal forces set up by the unequal weights of moving parts and vibration arising from elasticity or yielding of the parts themselves are the major causes of unbalance, of which the unequal weights of the parts are within the manufacturer's control. Unbalance of the conventional four-cylinder engine is of considerable magnitude, due to the angularity of the connecting-rod that produces unequal piston motion at the upper and lower parts of the stroke, the unbalanced force reversing itself twice per revolution and acting in a vertical direction. The actual magnitude of this force varies directly with the weight of the reciprocating masses and as the square of the speed.
Technical Paper

FUNDAMENTAL IMPROVEMENTS IN MANIFOLD DESIGN

1924-01-01
240004
Manifolds that have been designed as if they were intended to handle a fixed gas and that depend upon the application of excessive heat have not produced satisfactory results. Although heat in a limited amount aids vaporization, it is an agent that must be used with caution. As present-day fuels are composed of volatile constituents blended with the heavier ends, only a part at best can be vaporized and manifolds should be designed so that they will distribute wet mixtures of fog, instead of dry gases, uniformly at varying engine speeds and varying throttle positions. The four elements in the mixture furnished to the engine are air, water vapor, gasoline vapor and liquid particles of gasoline or fog. Liquid particles of considerable volume can be held in the airstream without depositing if the velocity is kept relatively high.
Technical Paper

WINTER TESTS SHOW GREATER DILUTION WITH HEAVY FUELS

1924-01-01
240003
Because the analyses of many samples of new and of diluted crankcase oil had not been completed by the Bureau of Standards when the results of the winter tests were reported at the 1923 Semi-Annual Meeting, the report on these dilution data was delayed. This information has since become available and forms the basis of this paper. After reviewing the results of the winter tests as already reported, stating the names of the cooperating companies and tabulating the cars and the mileage distribution in the test runs, the author discusses the results of the analyses of fresh crankcase oils and the dilution results before making a comparison between those obtained under summer and under winter conditions. Dilution versus mileage, the subjects of dilution, viscosity and specific gravity and the distillation of composite oil samples are presented next, followed by comments upon crankcase-oil consumption. Numerous tables and charts are included, and a summary of the results is made.
Technical Paper

INTERNAL-COMBUSTION ENGINE RADIATION CHARACTERISTICS

1924-01-01
240002
Radiation, although the subject of study for many years, is not yet thoroughly understood. The investigations of von Helmholtz 30 years ago showed that from 10 to 20 per cent of the total heat of combustion is due to radiation; but flames burning in the atmosphere show different characteristics from those subjected to a change of density in a combustion-chamber and the same conclusions do not apply. The possibility of a non-luminous flame's causing loss of heat during and after combustion was first noted by Professor Callendar in 1907. The principal theory as to the source of radiation is that it is due to the vigorous vibration of the gas molecules formed on combustion, and that, like the high-frequency radiations producing light, it is caused by chemical rather than thermal action. It has been shown that radiation emanates almost wholly from the carbon dioxide and the water molecules.
Technical Paper

CONTROL OF DETONATION

1924-01-01
240001
Investigations indicate that detonation may be controlled by retarding the rate of combustion by chemicals added to the mixture, which serve to increase its specific heat and prevent excessive temperature, and by reducing the temperature of the walls of the combustion-chamber, so that the temperature of the charge previous to ignition will be lower and thus insure a normal rate of combustion. The present discussion is devoted to methods of controlling the temperature of the charge before and after the mixture enters the combustion-chamber, and before normal ignition occurs. Tests previously made on a poppet-valve engine and on a sleeve-valve engine revealed the impracticability of applying the laboratory methods used at that time to commercial practice and the need of eliminating some of the difficulties inherent in those methods of detonation control. The various changes made in the engine are described, including the specially designed spark-plugs.
Technical Paper

THE GASOLINE RAILROAD-CAR FOR BRANCH LINES1

1924-01-01
240049
Gasoline rail-cars for branches of trunk-line railroads and for short-line roads have been the subject of much discussion since 1920. Mechanical officers of interested railroads, the engineers of companies building highway motor-trucks and others specializing on this subject have now developed designs to meet the different service requirements. Several hundred cars of various types have been built and are in service. The railroad with which the author is connected has in operation or on order 24 cars. Consideration of several principal factors of design is necessary if a selection is to result in obtaining equipment suitable for the particular service requirements of the carrier and if the knowledge accruing from the engineering development and operating experience of the past several years is to be of value.
Technical Paper

POSSIBLE ECONOMIES IN AUTOMOTIVE MACHINE-SHOP OPERATIONS1

1924-01-01
240050
This paper is confined to a discussion of machine-shop operations, and is intended to indicate by a few examples certain important economies that might be introduced in the shops of the automotive industry. It deals chiefly with the economies that can be effected without much capital outlay, though others are also mentioned. Calling attention particularly to the fact that, in the past, improvements of methods and of equipment have been confined largely to the more important operations on the more important parts and that relatively little study has been made of the smaller pieces and the less important operations, emphasis is placed on the necessity for carefully determining which tools and which makes of tool will best serve the purposes for which they are intended and for carefully sharpening the tools and providing means of setting them accurately.
Technical Paper

ECONOMICS OF TOOLING FOR INTERCHANGEABLE PRODUCTION1

1924-01-01
240051
When the volume and the variety of the parts produced by a plant increase beyond the point at which the shop mechanic is capable of devising the methods and building the tools for accomplishing the desired results, it becomes necessary to make a division of labor, and a special department on tool division is needed to determine the proper sequence of operations and the suitable equipment to produce the required quantity with the required degree of accuracy. It is necessary that the men be informed regarding the daily and the ultimate numbers of parts to be produced and the tolerances that will be allowed. The foremost consideration of the production engineer should be economy of production. In this phase of tool engineering, the ultimate number of parts to be produced plays an important role and equipment should be selected that will give the maximum production. All known methods of production should be compared and the most economical one chosen.
Technical Paper

COINING-PRESS OPERATION

1924-01-01
240052
Coining-press development is outlined and the author tells how such machinery was adapted to speed-up the production of automobile parts, such as forged arms and levers, by a squeezing process that superseded milling or spot-facing methods. The presses used are very rugged in construction and have the appearance of a plain-type punch-press, except for the knuckle that operates the ram. This knuckle is coupled to a crank by a connecting-rod or link. As the crank revolves, it straightens the knuckle. The pressure transmitted to the ram is many times greater than that which could be produced through a single-acting direct-connected crank-operated type of machine. An additional advantage of the knuckle movement is in the application of pressure at the end of the downward stroke. The position of the ram at the end of the stroke is controlled by a screw-actuated wedge.
Technical Paper

FUTURE PROBLEMS OF MOTORBUS ENGINEERING1

1924-01-01
240046
Substantial reduction of motorbus depreciation by materially increasing the useful life of the vehicle is an important problem now facing the automotive engineer. The author contrasts present motorbus life with that of street-cars; he finds a probable life of 4 or 5 years only for the former and 20 to 25 years for the average type of trolley-car. This, in the case of the motorbus, he says, is too short a period of usefulness and directly affects operating costs, since the increased cost of motorbus maintenance offsets its lower initial-cost. Demand for maximum comfort, safety and speed from the public and for economical operation from the operators has renewed interest in the six-wheel motorbus and given its design an impetus, although present four-wheel motorbuses of 25 to 30-passenger capacity have, and will continue to have, a very definite field and will not become obsolete due to replacement by other types.
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