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Technical Paper

MARINE HEAVY-OIL ENGINE INSTALLATION PRACTICE AND DEVELOPMENT POSSIBILITIES

1920-01-01
200046
The undisputed economy of the Diesel-type engine using heavy fuel oil is recognized, as no other power-generating unit of today shows better thermal efficiency. It is the result of the direct application of fuel in working cylinders. Transmission processes, such as the burning of fuel under a boiler to produce a working agent which must be carried to the prime mover, are less economical. The various factors which enter into a comparison between steam and heavy-oil installations are illustrated. The subject is treated in a more or less elementary manner. The diagrams and sketches are intended to explain the working principles of such examples of two and four-cycle engines as are now in actual operation in cargo ships, these being of the single-acting type. Double-acting and opposed-piston-type engines have been built and are being tried out. The working processes of two-cycle and four-cycle engines are illustrated and described in some detail, inclusive of critical comment.
Technical Paper

USE OF HEAVY FUEL IN AUTOMOTIVE ENGINES

1920-01-01
200049
Emphasizing the necessity of persuading fuel manufacturers to improve the suitability of internal-combustion engine fuel by the mixture of other materials with petroleum distillates, and realizing that efficiency is also dependent upon improved engine design, the author then states that results easily obtainable in the simplest forms of automotive engine when using fuel volatile at fairly low temperatures, must be considered in working out a future automotive fuel policy. The alternatives to this as they appear in the light of present knowledge are then stated, including design considerations. The principles that should be followed to obtain as good results as possible with heavy fuel in the conventional type of engine are then described. These include considerations of valve-timing and fuel distribution. Valve-timing should assist correct distribution, especially at the lower engine speeds.
Technical Paper

WAR DEPARTMENT MOTOR-TRANSPORT POLICY

1920-01-01
200050
In view of the inestimable services in the development of standardized transportation rendered to the Army by the Society of Automotive Engineers, particularly during the war, the author believes it important that the Society be acquainted with the intentions and policies of the War Department regarding the engineering development of motor transportation from the viewpoint of the problems and needs of the American Army. The fundamentals of the policies on motor transportation of February, 1919, as approved by the Chief of Staff, are stated and the subsequent changes discussed in some detail. Standardization of chassis as favored by the Army receives specific and lengthy consideration and the Government standardized trucks are commented upon. The standardization of body design and parts specifications are discussed in some detail. It is the policy of the Motor Transport Corps to maintain a thoroughly adequate and efficient engineering branch, which is now operative.
Technical Paper

MOTOR-BUS TRANSPORTATION

1920-01-01
200053
Since the Fifth Avenue Coach Co. of New York is the largest successful company operating motor-buses in this country, the author gives a rather comprehensive description of this company's systems and methods, stating the three main divisions as being the engineering, mechanical and transportation departments, and presenting an organization chart. Departments concerned with finance, auditing, purchasing, publicity, claims and the like, which follow conventional lines, are not considered. The engineering, research, mechanical, repair and operating departments are then described in considerable detail. Six specific duties and responsibilities of the research department are stated and six divisions of the general procedure in carrying out overhauls for the operating department are enumerated. Regarding fuel economy, high gasoline averages from the company's standpoint mean economy, well-designed and maintained equipment, and skilled and contented operatives.
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

DESIGN OF INTAKE MANIFOLDS FOR HEAVY FUELS

1920-01-01
200043
The adoption of the present system of feeding a number of cylinders in succession through a common intake manifold was based upon the idea that the fuel mixture would consist of air impregnated or carbureted with hydrocarbon vapor, but if the original designers of internal-combustion engines had supposed that the fuel would not be vaporized, existing instead as a more or less fine spray in suspension in the incoming air, it is doubtful that they would have had the courage to construct an engine with this type of fuel intake. That present fuel does not readily change to hydrocarbon vapor in the intake manifold is indicated by tables of vapor density of the different paraffin series of hydrocarbon compounds.
Technical Paper

DIRECT MULTIPLE-SPEED AUTOMOBILE REAR-AXLE DRIVES

1920-01-01
200041
The first car credited by the author as being equipped with two or more direct drives is the Sizaire-Naudin, in 1905. The transmissions of this car and of one embodying similar principles of gearing, brought out in 1909, are described and illustrated by diagrams. After the Sizaire-Naudin, the next double direct-drive transmission was the Pleukharp transmission axle, made in 1906, although the real ancestor of the present double-drive rear axles is the 1906 Pilain transmission; both are described and illustrated. Other early American and foreign forms are commented upon and diagrammed, including the Austin design, believed by the author to be the first to use a two-speed axle of the simplest and lightest possible type to provide two direct drives in connection with a separate gearset to give additional forward speeds and the reverse. Modern two-speed axles are reviewed, with critical comment and diagrams, and considerable discussion of gear ratios is included.
Technical Paper

JAPANNING PRACTICE

1920-01-01
200034
An analysis of japanning practice as a systematized industrial operation is presented as the result of an investigation. The nature of japans is discussed and an outline given of how the apparently contradictory requirements that japans must be weatherproof, somewhat flexible, sufficiently thick to be lasting, possess enough hardness to prevent excessive scratching under ordinary service conditions and take on a brilliant finish, can be fulfilled in an ordinary industrial plant without undue expenditure, so as to accomplish the original and primary objects of applying a finish to metal parts to prevent them from too great deterioration and supply a pleasing appearance to the finished product. Adequate provision for securing a uniform product is essential. The details of this are discussed. Three ways of applying japan are explained. The considerations involved in cleaning the metal and baking japan are enumerated at some length and the methods are described.
Technical Paper

PLYWOOD AND ITS USES IN AUTOMOBILE CONSTRUCTION

1920-01-01
200037
For many years plywood has been used for such automobile parts as roofs and dash and instrument-boards, but it was not until the closing of the European war that the extent to which this material was used in automobile construction greatly increased. The sudden requirement of airplanes created a large demand for plywood which would withstand the severest weather conditions. Glues were perfected that enabled plywood to withstand 8 hr. of boiling or 10 days of soaking in water without separation of the plies. Plywood as an engineering material is discussed. It is then compared in considerable detail with ordinary boards and also with metals and pulp boards, statistics and illustrations being given. The molding of plywood is considered with especial reference to employing plywood for surfaces having compound curvatures, and the limiting factors in the use of plywood for this purpose are mentioned.
Technical Paper

A TRACTOR ENGINE TEST

1920-01-01
200032
A four-cylinder 4 by 5-in. truck and tractor engine, designed for either kerosene or gasoline fuel and having the very low volumetric compression ratio of 3.36, was used. Only by suitable adjustments was it found possible to make it show a fuel consumption as low as 0.67 lb. per b.hp.-hr.; but with a slight variation in power and only a different carbureter adjustment the fuel consumption at 600 r.p.m. increased to about 1.2 lb., or 70 per cent, emphasizing the importance of knowing what constitutes the best engine adjustment and of disseminating such knowledge. The engine and its dimensions, the experimental apparatus and the method of testing are fully described and discussed, the results being presented in charts showing performance curves. These are described, analyzed and the results interpreted.
Technical Paper

DECREASING UNSPRUNG WEIGHT BY THE USE OF ALUMINUM

1920-01-01
200030
Stating the desirability of reducing unsprung weight in motor vehicles as a recognized fact and that 75 of 100 engineers interviewed favor such reduction, the particular advantages resulting are given as improved riding qualities, economy in tire wear and better acceleration. Mathematical deductions to establish the most desirable ratio of sprung to unsprung weight are not attempted, the intention being rather to state the reasons favoring lighter wheels and axles. Unsprung weight effects depend primarily upon the ratio of sprung to unsprung weight. No data determining the most desirable ratio are available, but an investigation of the proportional weight of the unsprung and sprung parts of good-riding-quality automobiles showed it to be about 1 to 3. By constructing the wheels and the axles of light metal it is possible to maintain such a ratio, assure good riding qualities and reduce the total weight.
Technical Paper

RELATION OF TIRES TO TRUCK EFFICIENCY

1920-01-01
200033
The discussion is largely in regard to the ability of a truck to deliver merchandise economically under a given set of external conditions. The matter of truck tire equipment is reviewed in the light of recent experiences of many operators and service men. The general functions of tires, securing traction, cushioning the mechanism and the load and protecting the road, are elaborated and six primary and seven secondary reasons given for the use of pneumatic tires on trucks within the debatable field of 1½ to 3½-ton capacity. The deciding factors in tire choice, those affecting time and those affecting cost, are stated and commented upon, the discussion next being focused on how tires affect these factors. Considerations relating to both truck and tire repairs are then reviewed.
Technical Paper

DESIGN OF PNEUMATIC-TIRED TRUCKS

1920-01-01
200031
After stressing the importance of transportation, the possible uses of the motor truck are considered. The increased cushioning and traction obtained from pneumatic truck tires accomplish faster transportation, economy of operation, less depreciation of fragile load, easier riding, less depreciation of roads and lighter-weight trucks. These six advantages are then discussed separately and various data to substantiate the claims made are presented. Following detailed consideration of transportation and operation economies, and depreciation of loads and roads, the practicability of pneumatic tires is elaborated, and wheels, rims and tire-accessory questions are studied. The four main factors bearing upon truck design for pneumatic tires are stated and discussed; emergency equipment for tire repair is outlined and a new six-wheel pneumatic-tired truck is described.
Technical Paper

THE HEAT-TREATING OF BRAZED FITTINGS FOR AIRCRAFT

1920-01-01
200022
A tendency exists in most shops to assume that brazed joints cannot be successfully heat-treated. As a consequence, many fittings used in aircraft work and assembled by brazing smaller parts together are finished and installed without being heat-treated after the brazing operation. This practice causes parts to be used that not only do not develop the available strength of the material, but which are in some cases, under internal stress due to the heating in the brazing operation. Recent experiments made at the Naval Aircraft Factory show that the assumption mentioned is entirely erroneous. The author considers this matter with a view to specifying the use of steels and brazing spelters which will permit the subsequent or perhaps the simultaneous heat-treatment of the parts.
Technical Paper

THE DIESEL ENGINE OF THE GERMAN SUBMARINE U-117

1920-01-01
200020
Shortly after the armistice, the author witnessed the surrender of the German submarine fleet and subsequently inspected 40 of the 170 submarines first surrendered. He also inspected 185 submarines in Germany. Practically all the engines were of the Machinenfabrik Ausburg-Nürnburg four-cycle Diesel type, of 300, 550, 1200 and 1750 hp. There were but five Krupp two-cycle engines. Brief comment is made regarding the design of these engines. The author, who supervised the dismantling of the German submarine U-117 at the Philadelphia Navy Yard, gives a detailed description of its engines, which were of the 1200-hp. type. This includes comments regarding materials, design details, valve mechanism, starting and reversing gear, lubrication, cooling and accuracy of workmanship. The air-compression system and some of its auxiliaries are outlined.
Technical Paper

COMMENTS UPON FUELS, LUBRICANTS, ENGINE AND PISTON PERFORMANCE

1920-01-01
200019
The comments the author makes regarding fuels, lubricants and engine and piston performance are suggested by pertinent points appearing in papers presented at the 1920 Annual Meeting of the Society. A list of these papers is given. The subjects upon which comments are made include salability of a car, engine balancing, pressure and chemical constitution of gasoline at the instant of ignition, the use of aluminum pistons, the success attending the various departures from orthodox construction, gasoline deposition in the crankcase and cleanness of design, as stated by Mr. Pomeroy; the performance of a finely atomized mixture of liquid gasoline and air and the contamination of lubricating oil by the fuel which passes the pistons, as discussed by Mr. Vincent; the dilution of lubricating oil in engine crankcases and the saving that can be effected by its prevention, as mentioned by Mr. Kramer; and tight-fitting pistons and special rings as presented by Mr. Gunn.
Technical Paper

NEEDS IN ENGINE DESIGN

1920-01-01
200016
The author advocates the use of the fragile aluminum crankcase as a spacer, running crankshaft bearing bolts clear through the crankcase and the cylinder base, so tieing the bearings firmly to the castiron cylinder-block and using the through-bolts also as holding-down studs for the cylinders. The results of experiments on six-cylinder engines with reference to the satisfactory utilization of engine fuel now on the market are then presented. The problem is how to carry the fuel mixture in a proper gaseous state from the carbureter into the cylinder without having the fuel deposited out meanwhile. The power developed at engine speeds of 400 to 2800 r.p.m., with and without hot air applied to the carbureter, is tabulated, the proper location of the intake manifold is discussed, and the necessary features of a satisfactory engine to utilize present-day fuel are summarized.
Technical Paper

THE VELOCITY OF FLAME PROPAGATION IN ENGINE CYLINDERS

1920-01-01
200010
Flame propagation has received much attention, but few results directly applicable to operating conditions have been obtained. The paper describes a method devised for measuring the rate of flame propagation in gaseous mixtures and some experiments made to coordinate the phenomena with the important factors entering into engine operation; it depends upon the fact that bodies at a high temperature ionize the space about them, the bodies being either inert substances or burning gases. Experiments were made which showed that across a spark-gap in an atmosphere of compressed gas, as in an engine cylinder, a potential difference can be maintained which is just below the breakdown potential in the compressed gas before ignition but which is sufficient to arc the gap after ignition has taken place and the flame has supplied ionization. These experiments and the recording of the results photographically are described.
Technical Paper

PREIGNITION AND SPARK-PLUGS

1920-01-01
200015
The author proposes to determine what features of spark-plug construction cause preignition and how this preignition manifests itself. To this end observed conditions on an Hispano-Suiza aviation engine following 4 hr. of an intended 6-hr. run are reported, with supplementary tests and observations. This resulted in experiments made to determine the cause of preignition, using spark-plugs constructed so that different features of their design were exaggerated. Illustrations of these plugs are shown and the results obtained from their tests are described. The different observed peculiarities are then stated, analyzed and compared with normal spark-plug performance. The experiments serve as a means of identification of special forms of preignition and as an indication of the abnormally high temperatures to which valves and combustion-chamber walls are thus subjected.
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