Search Results

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.

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.

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.

The author discusses the different types of material used in the production of the Liberty engine, the physical properties of the finished parts and the heat-treatments used in making them, applying the information as set forth to the automobile, truck and tractor industries. Under their several heads the different engine pans are discussed with close attention to details. Chemical analyses are given for each part and approved heat-treating temperatures are indicated. Quenching, direct and indirect, water and oil cooling, hard spots, warpage, scaling and hair-line seams are treated. The advantages and disadvantages of the Izod impact test are stated briefly.

The engine-fuel situation has changed almost overnight. Oil-consuming activities have taken on an accelerated expansion and the situation has shifted from excess supply to a position where demand is assuming the lead and is seeking a supply. A gasoline stringency, accompanied presumably by a marked rise in price, is a prospect to be anticipated. The production of gasoline is increasing more rapidly than the production of its raw material, crude petroleum. The available supply of the latter is very limited in view of the size of the demand. As a direct result of the situation, gasoline is changing in character and becoming progressively less volatile. The low thermal efficiency of the prevailing type of automotive apparatus contributes strongly to the demand for gasoline as engine fuel and has a bearing upon the quantity and the price of this specialized fuel.

The author first points out how increasing population and rising standards of living have increased the demand for foodstuffs and how such industrial activities as are brought about by the present conflict magnify the seriousness of the food problem, not only by withdrawing workers from the farms, but also by increasing food consumption on the part of those engaged in the speeded-up industries in order to supply the increased human energy required. The author then passes to a discussion of the tractor as a means for increasing the food supply by taking the place of withdrawn labor and cheapening production. Several charts show the effect of increased individual activity on food consumption, the relation of food consumption to standards of living and the growth of population, the variation of food demand during political activities during the past century, and the relation of the cost per calorie of various cereals.

The author limits his consideration of rear axles to that of the bevel-gear type and takes up the subject under the heads of load-carrying member, gearing, driving-shaft, brakes and materials. Several different forms of cast and pressed axle housings are briefly described. Mention is then made of the axle gearing and data given showing the end thrust for straight-tooth bevel pinions. The methods of supporting pinions and of attaching bevel gears to the differential are discussed. Forms of differentials are considered, several different conventional types being illustrated. The subject of driving shafts is briefly reviewed, as is also that of brakes and brake materials. The author concludes his paper by figures showing the tensile strength, elastic limit and elongation of the metals used in the various parts of the rear axle and also explains some oil-retaining and dust-protecting features of design.

An all-ceramic swirl chamber has been developed and analyses and evaluations concerning the strength of silicon nitride ceramic (Si3N4) have been performed with a view to using it for the entire internal wall surface of the swirl chamber. The strength characteristics of Si3N4 and their effect and variation have been determined. On the basis of measurements and analyses of thermal stresses, assembling stresses, etc., investigation of the most suitable construction and assembling methods to reduce load stresses on ceramic, and various kinds of duration tests, the swirl chamber has been confirmed to have the required durability. This engine was found to comply with the 1987 U.S. diesel particulate regulation.