APPLICATION of nuclear energy for civilian automotive uses has possibilities, these authors say. Nuclear power for automotive applications, they feel, is technically feasible now where size and weight are not prime considerations; where size and weight are major parameters, discoveries of new materials for construction of nuclear-power reactors must be made. New materials are needed for reactor fuels, heat extractants, neutron reflectors, reactor construction materials, controls, and radiation shields which must have unique nuclear properties in addition to conventional engineering properties. This paper presents nuclear automotive propulsion devices in terms of technologies now available. The necessary radiation-shielding mass and weight requirements are presented for an ideal point-source nuclear-heat-power engine.
IN LIGHT of the world's continually increasing demand for electric power and the attendant decrease in economically recoverable fossil fuels, the need for nuclear powerplants becomes all the more pressing. The author briefly covers in a general way several developments in design of different reactor types. Some problems inherent in generating power from fissionable isotopes are mentioned, together with the solutions which will enable the realization of electric current generation from the “burning” of nuclear fuels. Some startling theoretical schemes are mentioned which bid fair to making the generation and transmission of electric current in the future so different from our present methods as to mark the coming of age of yesterday's and today's science fiction.
RECENT improvements in techniques and instrumentation plus further data on rapid chemical chain reactions have made possible a clearer picture of the chemical reactions in engines. This paper describes the present knowledge of the changes in the fuel-air mixture prior to combustion, the effect of these changes on knock, and the method by which antiknocks function. Knock is controlled by the preflame reactions occurring prior to fuel combustion. These reactions are very complex, but the specific reactions causing knock seem to be simple, probably involving very fast reactions initiated by combinations of only hydrogen and oxygen. Hydrocarbon structure affects the rate of accumulation of enough of the hydrogen-oxygen species to cause knock. Tel slows the later stages of reaction, probably by deactivating the hydrogen-oxygen groups. The active antiknock species seem to be either lead oxide or metallic lead.
An investigation has been carried out under conditions comparable to normal engine operation to ascertain the effects of an additive such as nitromethane on the power output, fuel consumption, and efficiencies which result therefrom. It has been learned that nitromethane can increase power output by as much as 13 percent on an indicated or gross basis when added to methyl alcohol and by 7 percent when added to a benzene-isooctane mixture in concentrations of 20% by volume. By so doing, the indicated specific fuel consumption increases, but contrary to expectations, so does the indicated thermal efficiency. The results from the benzene-isooctane blend were comparable to those from the methanol in all respects except for the increase in power, which was not as great. The amount of nitromethane which can be added to a given fuel is a function of its tendency to bring about preignition in the engine.
TO use LPG efficiently as fuel for trucks, buses, or industrial engines, the compression ratio must be raised to take advantage of the fuel octane number. This point is explained in this paper, together with other pertinent facts relative to converting to LPG or using an engine already set up for the purpose. The author also details the many safety factors which have been considered in the handling of LPG. Developments to date provide that, with reasonable care and attention, LPG is as safe as, if not safer than, other types of fuel in common use. He touches on the economic advantages which can be realized now that LPG is in excess supply.
THIS paper discusses a number of factors involved in the problem of octane-number requirement increase due to combustion-chamber deposits. A laboratory single-cylinder engine test procedure, which evaluates the effects of various fuel and oil factors, is presented with data showing its correlation with passenger-car operation under light-duty, city-driving conditions. The influence of engine operating conditions during accumulation of deposits and the importance of engine conditions selected to evaluate the magnitude of the requirement increase are illustrated. It is indicated that organic materials formed from both fuel and oil are of major importance in deposit formation. Data are presented which show that tel added to pure hydrocarbons of different chemical types may have different effects. It is shown that the carbon/hydrogen ratio of leaded pure hydrocarbons influences the amount and composition of the deposit formed.
USERS of internal-combustion engines have long recognized the need for a fuel which possesses high-octane rating, resistance to detonation, and ideal combustion characteristics; a fuel which would minimize engine maintenance costs, and which would be plentiful enough to assure long-range price stability. This paper cites propane, a common liquefied petroleum gas, as possessing all these and many more advantages. The author points out the safety factors in the sealed fuel system, the lessening of noise resulting from smooth performance, and the elimination of exhaust smoke and odors from a fuel which burns carbon-free and smokeless. Comparative charts are provided covering fuel costs, storage costs, and fleet operating expenses.
ALTHOUGH the use of liquefied petroleum gas in automotive vehicles dates back to the early Thirties, it is only in recent years that there has been considerable interest in this application of LPG. The author lists the factors contributing to this increasing interest as follows: 1. Rising operating costs in the bus industry. 2. The increased supply of LPG. 3. The availability of engines of higher compression ratio. The author discusses both the fuel and the vehicles in which it can be used, placing particular emphasis on cost considerations.
THIS article is based on a panel discussion held Sept. 7 by SAE Detroit Section as part of its Summer Meeting at White Sulphur Springs, W. Va. Max Roensch of the Ethyl Corp. was panel moderator. Panel speakers were: J. M. Campbell CM Research Laboratories Division S. D. Forsythe Chicago Transit Authority Leonard Raymond Socony-Vacuum Laboratories
The application of the bunsen burner method of measuring flame velocities of gases is extended to liquid fuels by the use of a suitable vaporizer. The bunsen burner nozzle is enclosed and provision made for operation at elevated temperature, reduced pressure or both. The control apparatus which supplies a gaseous or liquid fuel as well as air for combustion is described in detail. The cone angle is obtained by measuring a “schlieren” image of the flame front which has been projected on a screen. Curves showing flame velocities as a function of air-fuel ratio for natural gas, gasoline, and acetylene are presented. Data were taken for temperature up to 900°F and for pressures down to 3.9″ Hg absolute.
THE investigations described here by Mr. Porter were initiated to evaluate the relative importance of pertinent diesel-engine variables, the relative effect of fuel properties, and to compare laboratory and service results on cold-starting performance. Tests disclosed: 1. Required cranking time is decreased with increased cranking speed, increase in surrounding temperature, and decrease in altitude. 2. The starting performance of undoped fuels is predicted by the delay cetane number. Increase of cetane number results in greater ease of starting. With doped fuels, however, the delay cetane number may or may not predict service starting performance. 3. It was indicated by tests on one make of engine that laboratory results may be used to predict service starting performance. 4. Various substances are effective as starting dopes, but the report indicates that an auxiliary applicator should be used, and warns that the effect of such materials on maintenance should be determined first.