Criteria

Text:
Display:

Results

Viewing 43621 to 43650 of 43870
1924-01-01
Technical Paper
240024
M L MCGREW
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.
1924-01-01
Technical Paper
240007
C S KEGERREIS
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.
1924-01-01
Technical Paper
240008
C E Sargent
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.
1924-01-01
Technical Paper
240002
THOMAS MIDGLEY, H H MCCARTY
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.
1924-01-01
Technical Paper
240004
A M DEAN, J W SWAN, C A KIRKHAM
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.
1924-01-01
Technical Paper
240005
H W ASIRE
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.
1924-01-01
Technical Paper
240017
O H SCHAFER
Graphical demonstration is given of the desirability of grinding gears that are made of carburized material. The warping of carburized gears is shown to be due to the shrinking of the carburized metal. The teeth cut on the regular commercial type of hobbing machine vary in form; those cut on a simplified hobbing machine are more accurate. Tooth forms made from oil-treated steel are much better than those made from carburized and hardened steel. The conclusion is that carburized gears must be ground, but when oil-treated and accurately cut on a simplified hobbing machine grinding may be necessary only when the teeth have become mutilated.
1924-01-01
Technical Paper
240010
A A BULL
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.
1924-01-01
Technical Paper
240013
N S DIAMANT
In the first part of the paper, a general quantitative comparison of air, water and oil-cooled cylinders is given as it relates to the subject of heat-transfer and temperature drop. Unfortunately, the discussion does not include experimental data, but the assumptions are stated clearly and a large range of values is covered in Table 2 so that any desired values can be chosen. A thorough and comprehensive discussion of the steam or the radio-condenser type of cooling is given under the headings of Steam Cooling Systems, Characteristics of Steam Cooling Systems, Cooling Capacity of Radiators Used To Condense Steam and Present State of Development. In the second part, an attempt is made to give a thorough but brief discussion of the performance or of the operating characteristics of radiators from the point of view of the car, truck or tractor designer. The cooling of aircraft engines is not considered.
1924-01-01
Technical Paper
240012
D E ANDERSON
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.
1923-01-01
Technical Paper
230034
J B FISHER
The two-fold purpose of the tests described was to acquire as many data as possible regarding the peculiar requirements of motorbuses, as viewed from the standpoint of power requirements and fuel economy, and to analyze the discrepancy found so often between the performance of an engine on the test block and the fuel economy obtained from the same engine under actual service conditions. Following a general statement of conditions to be met, and an examination of the problems of the manufacturer as to why his choice of the various units and accessories is such a vital factor in fuel economy, the improvements accomplished are enumerated, together with the reasons and inclusive of the desirable and undesirable features of carbureter specification and miscellaneous factors. The test equipment and methods are specified and discussed, the results obtained when using a steam cooling-system are presented and the general results are stated and commented upon.
1923-01-01
Technical Paper
230028
B G LEIGHTON
1923-01-01
Technical Paper
230041
Malcolm Loughead
ABSTRACT
1923-01-01
Technical Paper
230037
C P GRIMES
The author believes that the universal power unit will be direct air-cooled, but states that the direct air-cooled engine is now in the minority because, until very recently, there has not been a sufficiently broad series of established engineering facts and development work available to form a foundation for improvement. The satisfactory air-cooling of an 8 x 10-in. cylinder has been reported, and the development in a smaller cylinder of 138 lb. per sq. in. brake mean effective pressure; also, in a three-cylinder, air-cooled, radial-engine, a brake mean effective pressure of more than 125 lb. per sq. in. was developed and the engine endured beyond the ordinary expectations for water-cooled engines.
1923-01-01
Technical Paper
230038
R ABELL
Specification is made of 13 essential factors that the author believes are necessary for attaining better engine performance; he then describes how improved results have been obtained by the use of a single-valve mechanism on an engine having an unusually high compression-ratio and using ordinary gasoline as fuel. The latest type of engine built with the single-valve mechanism is illustrated, and detailed descriptions of its development, design and operation are given, together with comments upon its factors of advantage and data obtained from tests. In designing this single-valve mechanism, the primary object was to solve the problem of positively closing poppet-valves without using springs and thus to produce a type of engine that would operate efficiently at greater speeds than are possible with spring-closed valves. Another object was to reduce the temperature of the exhaust-valve.
1923-01-01
Technical Paper
230035
E F HALLOCK
Present-day fuels are stated to be the cause of crankcase-oil dilution, due to their high end-points, and the author presents tabular data to show how end-points have risen since 1910, together with data showing the effects of various percentages of fuel dilution with relation to the Saybolt viscosities and pour-points of high-grade oils. Three divisions are made of the dilution due to mechanical defects. Contamination, not dilution, necessitates oil drainage, and this statement is elaborated. The rise of heavier-bodied oils is decried. Six specific divisions of how to avoid crankcase-oil dilution are made and emulsification is discussed, together with demulsibility and crankcase service. Five specifications are made with regard to how to avoid oil-sludging, and carbonization is given lengthy consideration. Proper oil-specification is treated, and instructions on how to avoid oil-pumping and carbon deposit are presented in eight divisions.
1923-01-01
Technical Paper
230036
G B UPTON
Although the proper timing of the spark is as essential as the spark itself and the electrical and mechanical devices for producing the spark have been many, little attention has been given to the study of spark-advance. An error in timing of ± 20 deg. in a low-compression engine, or of ± 15 deg. in most other engines, has been shown experimentally to cause a loss of 10 per cent from the best power and economy, provided other conditions remained the same. Hand or semi-automatic control can average hardly closer than ± 15 deg. to the correct advance because the speed and the load combinations are constantly changing on the road. Two important phases mark the spark-advance problem.
1923-01-01
Technical Paper
230018
R S DRUMMOND
The author discusses only gear-grinding work on gear teeth subsequent to heat-treatment and pays particular attention to automobile transmission gears. He states that as yet very little is being done in the grinding of gear teeth that have not been heat-treated. The salvaging of gears that have been rejected and the finish-grinding of gears that have grinding stock remaining upon the teeth are commented upon, together with remarks on the cost of grinding, the history of gear grinding, the different classes of work performed, gear-grinding machines in general, tooth-form and gear wear. It is stated that gear grinding is commercially a production operation having as its aim the placing of the correct tooth-shape and proper surface-finish on gear teeth so that the gears can move accurately, noiselessly and without wear; and that the cost of finished acceptable transmissions is less than when the process of finish-grinding is used.
1923-01-01
Technical Paper
230017
S VON AMMON
A record of an investigation of heavy-duty truck-axles carried out by the Bureau of Standards at the request of the motor transport division of the Quartermaster Corps, this paper deals in particular with the mechanical efficiency of the axles tested. The investigation included, in addition to several worm-drive Class-B Army-truck axles with different types of bearing, a number of axles usually designated respectively as “internal-gear” and “multiple-reduction” type. Each of these types was represented by axles in successful use in commercial trucks of 5-ton rating. In analyzing the results of the tests it was found possible to separate the losses into no-load losses and load losses; the total loss being the sum of these two. In general, the no-load losses were primarily controlled by the viscosity and the method of application of the lubricant. They were greater in those axles in which the parts rotating at high speeds were immersed most completely in the lubricant.
1923-01-01
Technical Paper
230012
E H LOCKWOOD
Annual Meeting Paper - The heat-dissipating properties of three types of radiator core have been investigated at the Mason Laboratory, Yale University. These include the fin-and-tube, the ribbon and the air-tube groups, so classified according to the flow of the water and the air. The ratio of the cooling surface to the volume is shown to be nearly the same in the fin-and-tube and the air-tube cores, while that of the ribbon core is somewhat greater. A formula is derived for computing the heat-transfer coefficient, which is defined as the number of heat units per hour that will pass from one square foot of surface per degree of temperature-difference between the air and the water and is the key to radiator performance, as by it almost any desired information can be obtained. When the heat-transfer coefficients have been found for a sufficiently wide range of water and air-flows the cooling capacity of a radiator can be computed for any desired condition.
1923-01-01
Technical Paper
230011
S D HERON
Stating that most of the copying of aircraft practice in post-war car-design has proved a failure because the fundamental difference in duty has not been realized, the author proposes to show wherein the automobile designer and the engine builder can profit by the use of practice developed for air-cooled aircraft engines and, after generalizing on the main considerations involved, discourses on the simplicity of layout of the efficient air-cooled cylinder as a preface to a somewhat detailed discussion regarding cylinder design and performance, inclusive of valve location, type of finning and form of cylinder-head.
1923-01-01
Technical Paper
230019
Glenn Muffly
ABSTRACT
1923-01-01
Technical Paper
230050
A J OTT, C L OTT
A grinding-machine for finishing spur-gears is illustrated and described; claims are made that it will grind transmission gears on a production basis after they have been heat-treated and will produce correct tooth-contour, smooth finish and accurate tooth-spacing, these features being necessary in producing gears that are interchangeable and that run quietly. This machine is of the generating type, its action being that of rolling a gear along an imaginary rack and using the grinding wheel as one tooth of the rack. The dished grinding-wheel is reversible, 30 in. in diameter, mounted below the gear, and can be swiveled to the right or left of the center position up to an angle of 25 deg. The work-spindle carries the indexing and the generating mechanisms at the rear, where they are accessible and yet are protected.
1923-01-01
Technical Paper
230043
E FAVARY
The five types of final-drive now in use on motor vehicles are stated by the author to be (a) the chain-and-sprocket, (b) the bevel-gear, (c) the worm-gear, (d) the double-reduction and (e) the internal-gear. The advantages of each type as emphasized by its maker are presented and commented upon, and the same procedure is followed with reference to their disadvantages. Following these comparisons of the different drives, which cover about the first third of the paper, the bearing loads and shaft stresses of typical semi-floating and full-floating axles are calculated for the conditions (a) maximum torque plus the normal radial-load on the wheel, (b) the wheel locked and skidding forward when the brakes are applied and (c) the wheel skidding sidewise while the truck is moving. A tabulation of the results obtained from the mathematical calculations is included.
1923-01-01
Technical Paper
230055
WILLIAM P KENNEDY
The author surveys some of the general conditions prevailing in the street-railway field and the prospective development of a new type of service, in discussing the necessity for closer cooperation between the engineers of the automotive industry and the operating organizations of the railways, the idea being to develop flexible transportation-equipment that will coordinate with the operation of present railway-transportation facilities and to promote the utilization, wherever feasible, of railway power-supply in the employment of flexible bus-type equipment in supplementing and extending railway-organization service. Changing conditions are outlined, the influences tending toward flexible equipment are stated, and the differences of engineering practice pertaining in the railway and automotive fields are commented upon to show wherein railway and automotive engineers can cooperate.
1923-01-01
Technical Paper
230005
THOMAS MIDGLEY, ROBERT JANEWAY
In the case of the internal-combustion engine, where virtually every separate portion of explosive mixture behaves differently, the usual thermodynamic interpretations of the pressure-volume indicator-card, as applied to steam engineering, have little value. In internal combustion, the pressure-volume diagram is of value only as an expression for the product of the force exerted upon the piston-top times the distance through which the piston moves. The paper (Indiana Section) begins with the fundamental phenomena and develops from them a diagram such that each fuel-mixture particle can be properly exposed for analysis during the process of combustion. This is termed the pressure-volume-quantity card, and it is described in detail and illustrated. An extended consideration of its surfaces follows, inclusive of mathematical analysis.
1922-01-01
Technical Paper
220011
NEIL MACCOULL
That all of the variable factors of automobile friction-losses such as the quantity and viscosity of lubricants, the efficiency of worm-gearing and part-load Modifications are not appreciated, is indicated by an examination of the literature on this subject which reveals a lack of necessary data. Experiments to determine the mechanical losses, including all friction losses between the working gases in the engine and the driving-wheels of the vehicle, are described and supplementary data are included from Professor Lockwood's experiments at Yale. Three distinct possibilities for increasing the fuel economy of a motor vehicle are specified and enlarged upon, gearset experiments to secure and develop data for a four-speed gearset being then described and commented upon at length; photographs and charts illustrative of the equipment used and the resultant data are included.
1922-01-01
Technical Paper
220012
S D HERON
The paper reviews some of the salient points arising in the design and development of the modern high-output air-cooled cylinder. It is based to a very large extent upon the work of Dr. A. H. Gibson at the Royal Aircraft Establishment, which in turn was principally a development of the pioneer efforts of Renault, supplemented by some post-war work of the author for British companies and tests made by the engineering division of the Air Service. While the paper may, therefore, lack somewhat in originality, many of the results presented, it is stated, have not been published previously. The problems of an aircraft cylinder of approximately 40 b.hp. are dealt with primarily, but some aspects of automobile-engine cylinder design are considered. The first point treated is the heat to be dissipated, this being followed by a consideration of how to secure an even temperature-distribution in the various parts of the cylinder.
1922-01-01
Technical Paper
220006
O C BERRY, C S KEGERREIS
Stating that present internal-combustion engine fuel is too low in volatility for economical use and that this is the cause of engine-maintenance troubles, the authors believe that, since it is not possible to obtain the more volatile grades in sufficient quantity, the only hope of remedying this condition is to learn how to use the heavy fuel, and that the most promising method of doing this lies in the effective use of heat. As the experimental data regarding the best temperature at which to maintain the metal in a hot-spot manifold and the range of temperatures available in the exhaust gases are meager, the authors experimented in the Purdue University laboratory to secure additional data. They present a summary of the results.
1922-01-01
Technical Paper
220003
THOMAS MIDGLEY, W K Gilkey
The paper is intended to familiarize automotive engineers with the general subject of spectroscopy, by pointing out the various methods that can be employed to determine the actual instantaneous pressures obtained in normal combustion, the temperature-time card of the internal-combustion engine and the progress of the chemical reactions involved in normal and abnormal combustion. The subject of spectroscopy is outlined and explained, illustrations are presented of different types of spectra, and spectroscopes and their principles are discussed. The remainder of the paper is devoted to an outline of what the spectroscope can reveal about the nature of combustion.