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Technical Paper

SPECTROSCOPIC INVESTIGATION OF INTERNAL COMBUSTION

1922-01-01
220003
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.
Technical Paper

MOLECULAR MOVEMENTS DURING COMBUSTION IN CLOSED SYSTEMS

1922-01-01
220002
The paper is an exposition of the theoretical analysis made by the author of the experimental work of Woodbury, Canby and Lewis, on the Nature of Flame Movement in a Closed Cylinder, the results of which were published in THE TRANSACTIONS for the first half of 1921. No experimental evidence is presented by the author that has not been derived previously by other investigators. The relation of pressure to flame travel is derived first, the relation of mass burned is considered and a displacement diagram constructed, described and analyzed. The break of the flame-front curve, called the “point of arrest,” enters prominently into the discussion and computations; the pressure in the flame-front is studied; the reaction-velocities are calculated; and general comments are made.
Technical Paper

FUEL RESEARCH DEVELOPMENTS

1921-01-01
210012
Two distinct problems are involved in fuel research work, multi-cylinder distribution and the chemical constitution of the fuel mixture after it enters an engine cylinder. In discussing elementary combustion, the author refers to the components of the energy of combustion as gravitational, kinetic and barometric, and elaborates his theme with the aid of diagrams and charts showing normal and abnormal combustion. After emphasizing the necessity of theorizing at some length, anti-knock substances are discussed, inclusive of substances apparently dissimilar that have the same chemical constituents. The ignition point and fuel utilization are treated, followed by comments upon fuel studies that have been made, with accompanying indicator-cards. The future objectives of fuel research are outlined as being along lines of physical and of thermo-chemistry, the simple laws of elementary physics, and cooperation with the producers and refiners of the fuel.
Technical Paper

AUTOMOBILE EXHAUST GASES AND VEHICULAR-TUNNEL VENTILATION

1921-01-01
210006
The data given in this paper were obtained from an investigation by the Bureau of Mines in cooperation with the New York and New Jersey State Bridge and Tunnel Commissioners to determine the average amount and composition of the exhaust gases from motor vehicles under operating conditions similar to those that will prevail in the Hudson River Vehicular Tunnel. A comprehensive set of road tests upon 101 motor vehicles including representative types of passenger cars and trucks was conducted, covering both winter and summer operating conditions. The cars tested were taken at random from those offered by private individuals, corporations and automobile dealers, and the tests were made without any change in carbureter or other adjustments. The results can therefore be taken as representative of motor vehicles as they are actually being operated on the streets at the various speeds and on grades that will prevail in the tunnel.
Technical Paper

FLAME

1921-01-01
210045
Stating that the knowledge now available does not permit an exact scientific definition of flame and giving the reasons, in this paper the author regards flames as gases rendered temporarily visible by reason of chemical action, discusses their physical rather than their chemical aspects and, unless otherwise indicated, refers to the flames of common gasoline and kerosene only. To gain a reasonably clear understanding of the requirements and characteristics of the different kinds of flame, it is necessary to begin with a study of atoms and molecules. The author therefore discusses the present atomic theory, the shape of the atom and molecular structure, and follows this with a lengthy detailed description of the beginning of combustion. The requirements and characteristics of the inoffensive variety of combustion are considered next and nine specific remedies are given for use in accomplishing the burning of heavy fuels with a blue flame in present engines.
Technical Paper

ELEMENTS OF AUTOMOBILE FUEL ECONOMY

1921-01-01
210048
The paper analyzes and states the factors affecting the power requirements of cars as rubber-tired vehicles of transportation over roads and the factors affecting the amount of power supplied the car as fuel to produce at the road the power required for transportation. Quantitative values are given wherever possible to indicate the present knowledge of the relation between the factors involved, and the text is interspersed with numerous references, tables, charts and diagrams. Among other important factors specifically discussed are mixing and vaporization, charge quantity control, the heat of combustion, gas-pressure, transformation loss and power transmission efficiency. Six appendices contributed by other associates of the Bureau of Standards are included.
Technical Paper

HIGH-SPEED INDICATORS

1920-01-01
200011
The indicator was an important factor in the early development of the internal-combustion engine when engine speeds were low, but on high-speed engines such indicators were unable to reliably reproduce records because of the inertia effects of the moving part of the pressure element. The first need is for a purely qualitative indicator of the so-called optical type, to secure a complete and instantaneous mental picture of the pressure events of the cycle; the second need is for a purely quantitative instrument for obtaining an exact record of pressures. The common requirements for both are that the indicator timing shall correctly follow the positions of the crank and that the pressure recorded shall agree with the pressures developed within the combustion space. Following a discussion of these requirements, the author then describes the demonstration made of two high-speed indicators, inclusive of various illustrations that show the apparatus, and comments upon its performance.
Technical Paper

STEAM AUTOMOTIVE SYSTEM

1920-01-01
200014
It is stated that the general performance of the steam-propelled automobile has never been equalled by that of the most highly-developed multiple-cylinder gasoline cars and that it is significant that no innovation in the gasoline car has yet been able to give steam-car performance. This led to an effort to remove the troublesome features of the steam car, rather than to complicate the gasoline car further by attempting to make it duplicate steam-car performance. The paper describes in detail the steam automotive system developed by the author and E. C. Newcomb, including the boiler, the combustion system and its control, the engine and the condensing system.
Technical Paper

COMBUSTION OF FUELS IN INTERNAL COMBUSTION ENGINES

1920-01-01
200069
The automotive industry was considered a mechanical one until fuel difficulties caused a realization that the internal-combustion engine is only a piece of apparatus for the effective utilization of chemistry. The only great cloud on the horizon of the automotive industry today is the fuel problem, one way to dispel it being to increase the supply and the other to make the automotive device do what it has been designed to do. The author reviews the production of oil and of automotive apparatus, considers the available fuels and states the two distinct parts of the fuel problem as being first carburetion and distribution, external to the engine and one of purely physical relationship, and, second, the combustion of fuel inside the engine cylinder. The subjects of regulating combustion by additions to the fuel, the chemistry of fuels and the burning of heavy fuels are discussed at length.
Technical Paper

KEROSENE AS A TRACTOR FUEL

1920-01-01
200078
Kerosene has advanced to the front rank as a fuel for the farm tractor within a decade. A heavily preponderating majority of tractors burn kerosene. The history of early oil engines is reviewed and some comparative costs of kerosene and gasoline fuel for tractors, obtained from tests made in January, 1920, are given. Kerosene tractor-engine development is then discussed. The conditions required for complete combustion are the same in principle for both kerosene and gasoline, but in actual practice a wider latitude in providing ideal conditions is permissible for gasoline than for kerosene. The four classes of commercial liquid fuels usable in internal-combustion engines are the alcohols, the gasolines, the common kerosenes and the low-cost heavy-oil fuels. The alcohols rank lowest in heating value per pound of combustible. Under existing economic conditions neither alcohol nor the fuel oils require consideration as available fuels for the tractor.
Technical Paper

SOME FACTORS OF ENGINE PERFORMANCE

1920-01-01
200042
A large number of tests were made in the altitude laboratory of the Bureau of Standards, using aircraft engines. The complete analysis of these tests was conducted under the direction of the Powerplants Committee of the National Advisory Committee for Aeronautics. Many of the engines were of the same make, differing in compression ratio or dimensions. The testing program included determinations of the brake-horsepower at various speeds and altitudes, or air densities, and the friction power, or the power required to operate the engine with no fuel or ignition at various speeds and air densities, with normal operating conditions of oil, water and the like. Some tests included determination of the effect of change of mixture ratio and of air temperature, and of different oils. The difficulties caused by the necessity of using indirect methods to ascertain the effect of various factors are outlined. The test analyses and curves are presented.
Technical Paper

FACTORS INVOLVED IN HIGH AIRPLANE SPEED AT GREAT ALTITUDES

1920-01-01
200045
The development of the supercharger for aircraft engines has led to the possibility of hitherto unheard-of speed of transportation. An analysis of a definite case is presented to show the different aspects of the problem in a practical form, with a view toward determining what can reasonably be expected. An attempt is also made to arrive at a knowledge of the elements involved whose improvement will effect the greatest gain. The supercharger overcomes the deficiency of the ordinary gas engine's serious loss of power at great altitudes, due to its inability to obtain sufficient oxygen for the combustion of a normal charge of gas which, in an engine of conventional design, is essential to the development of its maximum output.
Technical Paper

ENGINE DESIGN FOR MAXIMUM POWER AND FUEL ECONOMY

1920-01-01
200058
Design factors are considered from the thermodynamic standpoint only, which excludes several factors affecting power and economy. The problem of air heating includes a consideration of its influence on pressure, the consequent lowering of pressure being counteracted to some extent by the resulting improvements in carburetion and distribution and by more rapid and complete combustion; the effects of delayed combustion, with a study of the thermodynamic conditions and possible improvements; and the results that are actually obtainable from lean and rich fuel mixtures. Fuel economy is difficult because its factors conflict with those of power. The benefit of the expansion of any elastic working medium to economy is emphasized. Charts from previous papers, showing the ratio of air to fuel by weight, are referred to and discussed, best economy being obtained with mixtures leaner than those giving maximum power.
Technical Paper

FACTORS INVOLVED IN FUEL UTILIZATION

1920-01-01
200060
From a laboratory examination of the controlling relationships between carburetion and engine performance still in progress, the general conclusions so far reached include fuel metering characteristics, the physical structure of the charge, fuel combustion factors and details of engine design and manufacture. In every throttle-controlled engine, the variation in fuel metering for best utilization is inversely functional with the relative loading and with the compression ratio, but the nature of the fuel leaves these general relationships undisturbed. The physical structure of the charge influences largely the net engine performance and the order of variation of the best metering with change in load. Perfect homogeneity in the charge is theoretically desirable but entails losses in performance.
Technical Paper

THE HIGH-COMPRESSION OIL ENGINE

1919-01-01
190039
THE ever-increasing demand for highly volatile fuels and constantly decreasing volatility, constitute a serious problem. Synthetic fuels have been suggested as a remedy, but these require a change in carburetion methods. It is the author's conviction that, if any redesigning is necessary, this should embody a combustion method by which any of the existing liquid hydrocarbons can be utilized and further change of method obviated, if a new fuel should later be developed. The high-compression engine is presented as a solution. Proof is offered that by its adoption any liquid hydrocarbon fuel can be utilized under any temperature condition and a real saving in fuel accomplished through increased thermal efficiency. Sustained effort should be made along these lines to increase thermal efficiency and provide an engine of adequate power, flexibility, ease of control and ability to operate on any of the fuels obtainable now or later.
Technical Paper

ENGINE PERFORMANCE

1919-01-01
190030
EVERY plow in use should have 10 b.-hp. available. Every tractor engine should deliver continuously at least 33 hp. If the 330-cu. in. engine mentioned were as good as a Liberty airplane engine, it could deliver 57 hp. at 1000 r.p.m. The horsepower actually obtained is as follows: 41.5 in the laboratory 33.0 at the factory 29.0 when burning gasoline 23.0 when burning kerosene 21.0 with poor piston-rings 19.0 with poor spark-plugs 9.5 available at the drawbar The great engineering problem of the future lies between the 57 and the 23 hp. From 19 to 9.5 hp. is the manufacturer's problem. The main difficulties, as outlined by the figures given, lie in the combustion chamber and its ability to dissipate the surplus heat, and in the limitations of fuel. There will be no need for refiners to continue to break up the heavier fuels by processes already so successful, if by ingenuity and good understanding of thermodynamics these can be made to burn in present-day engines.
Technical Paper

HOT SURFACE OIL ENGINES FOR INDUSTRIAL PURPOSES

1919-01-01
190036
THE oil engines described are for stationary or land installations and are of the “hot-surface” design with combustion at constant volume. Progress in the design is referred to and the thermal efficiency of modern designs is compared with that found in engines twenty-five years ago. Three important features are reviewed, namely: (a) Reliability, (b) first cost and (c) economy. Improvements in the design of spraying devices, and other details of construction which have brought about greater reliability, are referred to. Dimensions of large two and four-cycle oil engines are given, and the first costs of each type are contrasted. The greater economy of the modern oil engine as compared with the earlier type is explained. Indicator cards, test data, speed, weights and other details of interest are enumerated concerning the De La Vergne SI type of oil engine, this being an example of the results obtained in a modern hot-surface-type oil engine.
Technical Paper

WORKING PROCESSES OF INTERNAL-COMBUSTION ENGINES

1919-01-01
190058
A new type of automotive engine should be the quest of all designing engineers. Investigation has revealed the fact that 68 per cent of all tractor engine troubles occur in magnetos, spark-plugs and carbureters, the accessories of the present-day automotive engine. Four-fifths of the fuel energy supplied is regularly wasted, yet the fuel is a liquid meeting severe requirements of volatility, etc., and is already becoming scarce and costly. In an airplane, fuel is carried by engine power. In ocean-going cargo vessels it increases available revenue space. It is at once clear that for purely practical reasons the question of fuel economy, no less than the question of the nature of the fuel, becomes momentous. What fuel will do is entirely a question of what process it is put through in the engine; in what way combustion is turned into power.
Technical Paper

HEAVY-FUEL CARBURETER-TYPE ENGINES FOR VEHICLES

1919-01-01
190069
Manufacturers of carbureters and ignition devices are called upon to assist in overcoming troubles caused by the inclusion of too many heavy fractions in automobile fuels. So far as completely satisfactory running is concerned, the difficulty of the problem with straight petroleum distillates is caused by the heaviest fraction present in appreciable quantity. The problems are involved in the starting, carburetion, distribution and combustion. An engine is really started only when all its parts have the same temperatures as exist in normal running, and when it accelerates in a normal manner. Two available methods, (a) installing a two-fuel carbureter, using a very volatile fuel to start and warm-up the engine, and (b) heating the engine before cranking by a burner designed to use the heavier fuel, are described and discussed.
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