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The paper is divided into three parts; the fuel problem, the selection of the most economical internal-combustion engine for adaptation to automotive purposes and the details of the development work undertaken. After stating the fuel problem, inclusive of production, volatility and price charts, the methods of increasing the engine-fuel supply, the characteristics of present engine fuels and general considerations regarding the selection and adaptation of the most economical engine are discussed. Classifying internal-combustion engines as being of low, medium or high compression, the essential factors, advantages and disadvantages of each class are commented upon in detail. High-compression engines are classified, as to their method of injecting the fuel into the combustion-chamber, into the three general classes of air, gas-pressure and mechanical injection.

About 1917 the heavy ends of the fuel sold as gasoline required such an amount of heat to vaporize them that the expression “crankcase dilution” appeared; now they have increased to a maximum boiling-point of 446 deg. fahr., which has made it necessary to go still farther in the direction of heat application. After a brief consideration of the relative heat-absorption of air and fuel and the time factor in its relation to vaporizing, the author describes experiments with a specially designed manifold for increased vaporization efficiency and presents photographs of the device. With this type of manifold it has been possible to eliminate crankcase oil dilution completely and effect a reduction in carbonization. The lubrication efficiency has been improved, as well as other features that are enumerated.

The author selects and sets forth some of the main laws and basic considerations influencing carbureter action. A brief defense of the carbureter as a means of supplying fuel to an engine is made, as compared with the fuel-injection method, and conditions in the cylinder, the manifold and the carbureter during normal operation are stated. The relations of throttle positions, manifold vacuum and engine torque are discussed, followed by an exposition of the effect of manifold vacuum upon vaporization. The subject of air-flow in carbureters is treated at some length and the venturi-tube form of air-passage is commented upon in considerable detail. The flow of air through air-valves, fuel-flow and mixture-proportion requirements are given detailed consideration, the last being inclusive of passenger-car, motor-truck, tractor, motorboat and airplane needs. The essentials for obtaining accurate information with regard to carbureter and engine tests are outlined.

The majority of the reputable truck builders are attempting to build a high-quality product that will operate over a period of years with the minimum of maintenance expense; however, many designers lose sight of the effect of shocks and strains, which is of even greater importance. Stating that a truck is scrapped for some one or a combination of the three reasons of obsolescence of design, wear on vital parts that cannot be replaced economically and failure of parts due to shock loads, fatigue or crystallization, the author comments upon these and then discusses chassis strains under five specific headings, illustrations also being given.

The paper surveys the differences between American and European conditions in the automotive industry and then considers briefly the reasons for them. The governing conditions are stated and their effects are traced. The subjects discussed include motorcycles and small cars, road conditions, car idiosyncracies, selling conditions in Europe, and a comparison of design in general. The differences of practice are stated and commented upon. Six specific points are emphasized in the summary. The author states that the outlook for American cars the world over is seemingly good. In recent American designs, equal compression - volumes are often assured by machining the heads; six-cylinder crankshafts have seven bearings and are finished all over in the circular grinding machine; pressure lubrication is used for all moving parts of the engine; and in all ways the highest practice is aimed at. America is trying to improve the quality without increasing the cost.

The author describes a process for drying coats of paint and varnish more rapidly than is possible with natural means, by adding heat and moisture simultaneously to the air surrounding the siccative coatings, through the employment of mechanical devices. The use of a fan and conditioning equipment to produce air circulation allows the process to be adapted readily to modern factory-schedules. Atmospheric conditions suitable for drying are discussed at some length as being a composite of sensible temperatures and relative degrees of humidity, and several humidifying devices are described and illustrated. Color control of paint by this means of drying is mentioned, examples being given, and numerous photographs showing installations of artificial drying equipment in use at various automobile plants are presented.

The author considers first the materials available for construction, in connection with the S.A.E. standard specifications, and presents a comparison of the different metals with comments thereon. In regard to metallurgical problems the designer's first task is to determine what the various stresses in the parts are and their magnitude; hence, a true appreciation of the terms “shock” and “fatigue” is necessary; a somewhat lengthy explanation of their meaning is given. The construction features of the different parts of the tractor are treated in general, no attempt being made to cover details; comments are presented on front axles, wheels, bearings, cylinders, valves, valve-seats, transmissions and gears. Heat-treating is then considered in some detail, three specific reasons for annealing before machining being given and five which are governing factors in regard to heat-treatment in general.

Before taking up the results of the tests, the author states briefly the provisions of the Nebraska tractor law, the kind of tests conducted and the equipment used. Applications covering 103 different tractors were received during the season; of the 68 that appeared for test, 39 went through without making any changes and 29 made changes. The results of the tests are described and illustrated by charts. The fuel consumption was studied from the three different angles of volumetric displacement, engine speed and the diameter of the cylinders, the tractors being classified accordingly and the results presented in charts which are analyzed. The weaknesses of the tractor as shown by the tests are commented upon at some length with a view to improvement of the product.

Stating that it is conceded by engineers that weight reduction is desirable economically but that it is not unusual to find that weight reduction is looked upon as incompatible with reliability and road-holding properties, the author outlines briefly the normal weight-distribution in an automotive vehicle and gives a short analysis of the power required to drive it having in mind the necessity of reducing the absolute friction-loss. The use of aluminum for various parts is debated, especially those in which reliability is distinctly a function of lightness and not of weight such as engine pistons, and the application is made general to cover all parts of an automobile in which the stresses are determined by road shocks and speed. The trend of design in general and recent research in particular are stated to be along the lines of weight reduction without any sacrifice of essentials.

The author describes the type, size and general characteristics of the engines with which the German submarines were equipped at the time of the surrender, after having personally inspected 183 of them at that time, and then presents the general details of construction of these engines, inclusive of comments thereon. The maneuvering gear for such engines receives lengthy consideration and the reliability of engines of this type is commented upon in some detail, the author having confirmed his opinion that the German submarine engine is extremely reliable. One of the controlling factors in the design is that the Germans had investigated steel casting to the point where the successful production of steel castings was an ordinary process, and the author believes this to have been largely responsible for the success of the German submarine engine.

This paper is a collection of notes gathered from investigation of the subject in the literature on the development of internal-combustion engines and memoranda set down during a long series of tests. The paper includes a discussion of the physical and chemical aspects of the subject and sets forth a working theory that has proved of value. Several methods of measuring turbulence are stated. After outlining the history of the subject and giving references, the effect of turbulence on flame propagation is discussed at length and illustrated by diagrams. Two methods of producing turbulence are then copiously illustrated and described, inclusive of seven diagrams showing characteristic turbulence in typical cylinders. Following the description of the methods of measuring turbulence, the effects of turbulence in performance are summarized under 10 specific divisions.

The distinguished author begins with a short account of the principal actions common to all internal-combustion engines and then proceeds to a more detailed account of the experiments that have been made to develop the theory and establish the properties of the flame working fluid of those engines. The divisions of the paper are headed (a) short statement of cylinder actions, (b) the air standard, (c) flame, the actual working fluid, (d) knocking, pinking and detonating, (e) air and exhaust supercompression, (f) residual turbulence, (g) gaseous explosions, (h) flame propagation and recompression, (i) the specific heat of flame, and (j) conclusions. After treating (a) in considerable detail, the author discusses present efficiencies and knowledge in regard to the limits of the thermal efficiency possible in internal-combustion engines under (b), (c), (d) and (e), going into considerable detail and presenting and analyzing numerous diagrams and charts.

The general requirements for ideal carburetion are considered first, as an introduction to what the Packard fuelizer is and how it functions. Since it is difficult to secure uniform distribution with what is termed a wet mixture, this problem is discussed in general terms and it is stated that the fuelizer was evolved only after several different types of exhaust-heated manifold had been tested and found wanting. Detonation is treated at some length, four specific rules being stated that apply to the most desirable mixture temperatures to be maintained, and the source of the ignition spark for the fuelizer is discussed as an important element in the device. Further consideration includes comments upon the comparative merits of the hot-spot and the fuelizer, “hot-spot” being intended to mean any of the exhaust-heated manifold-designs in which the heat is more or less localized.

In addition to using a smaller quantity of fuel per horsepower-hour, the small high-speed internal-combustion engine has other important features of advantage which are stated. The authors outline specifications intended to secure these advantages. The high-speed racing engine designed by the authors, which won the 500-mile race on the Indianapolis Speedway in 1920, is illustrated and described in detail, its distinctive features being commented upon. The automobile should be built to a higher standard for the use of the high-speed engine. The builder should work to a greater degree of precision and, as the working parts of the engine are all light and stressed fairly highly, this necessitates the use of properly heat-treated high-grade materials. Few small cars of this type seem to give satisfaction. The authors look for further developments to counteract this in the near future.

The author uses some analogies of mechanical things to illustrate the underlying facts that must be considered in connection with electrical ingition, the first being that of an automobile starting under the influence of a constant force, which is analogous mechanically to the old touch-spark ignition circuit in that the velocity of the automobile corresponds with the velocity or speed at which the electricity is moving through the circuit. In similar manner the analogy is extended to include car acceleration and its acquirement of a certain store of energy as an illustration of electrical-energy storage as the current through an induction-coil is increased; and further analogies are made, numerous diagrams being presented. Battery and magneto-ignition similarities are treated in a similar way, short and long sparks are discussed pro and con and spark lag is considered in general terms.

Statistics taken from a report made by the Department of Agriculture regarding the number and size of farms in the United States indicate that approximately 2,580,000 farms are available as a market for the isolated gas-electric lighting plant. The common types of lighting plant are classified in three groups, each of which is subdivided into three classes, and these are illustrated, described and discussed. The characteristics of the ideal farm lighting-plant are enumerated and discussed as a preface to a somewhat lengthy consideration of the factors that influence the design of the component parts, which are grouped as pertaining to the engine, the generator, the switchboard and the battery. Storage batteries are still considered the weakest part of the isolated plant and they are specially commented upon. The author emphasizes that much still remains to be accomplished as regards the stability of design, reliability and economy of the isolated plant.

Aviation has no perfect analogy, for it has no precedent. Two classifications are made. Scheduled service includes the carrying of mail, express or passengers on a definite and regularly maintained schedule, independent of, or supplementary to, other forms of transportation. Special service includes pleasure flights, oil-field survey, selecting industrial land-sites, planning cities, aerial photography, forest-fire patrol, visiting remote points, exploration, aerial advertising, delivery of perishable products, real-estate survey and industrial purposes. Each of these classifications requires different equipment, organization and operating personnel. The equipment requirements and the reliability of aerial transportation are discussed, the necessity for suitable terminals and federal flying regulations are emphasized, the subject of insurance is commented upon and the development of aerial commercial transportation is outlined.

First reviewing the history of the progressive insufficiency of the supply of highly volatile internal-combustion engine fuels and the early efforts made to overcome this by applying heat to produce rapid vaporization, the author gives an outline of the methods already found valuable in offsetting the rising boiling points of engine fuels and states the resulting three-fold problem now confronting the automotive industry. The tendency to subordinate efficient vaporization to the attainment of maximum volumetric efficiency is criticised at some length and the volatility of fuel is discussed in detail, with reference to characteristic distillation, time of evaporation and distillation-temperature curves which are analyzed. Heating devices are then divided into four classes and described, consideration then being given to fuel losses outside the engine.

The author first considers the style and arrangement of the seats, the position of the rear axle as affecting the rear kick-up in the chassis frame, and the position of the rear wheels as determining the distance from the back of the front seat to a point where the curve of the rear fender cuts across the top edge of the chassis frame. The location of the driver's seat and of the steering-wheel are next considered, the discussion then passing to the requirements that affect the height of the body, the width of the rear seat, and the general shape. The evolution of the windshield is reviewed and present practice stated. Structural changes are then considered in relation to the artistic requirements, as regards the various effects obtained by varying the size or location of such details as windows, doors, moldings, panels, pillars, belt lines, etc., and the general lines necessary to produce an effect in keeping with the character of the car.

Engine lubrication troubles resulting from the dilution of the lubricating oil in engine crankcases appear with increasing frequency, particularly where economy demands the use of cheap grades of fuel. Unless a lubricant not miscible with present engine fuels can be produced, lubricants will steadily decrease in viscosity whenever fuel finds its way into them. The most satisfactory remedy is to prevent dilution of the oil. To prevent absorption of the fuel by the oil is a problem of engine design. In experiments made by the Bureau of Standards the absorption of fuel vapors at average engine temperatures was found to be negligible; further experiments and oil tests showed no indication of dilution due to cracking, with representative refiners' products from typical crude oils available in this country.