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Annually, the Coordinating Research Council (CRC) sponsors a nationwide survey of octane number requirements for current model passenger cars. In this review, based on surveys from 1965 through 1974, trends in octane number requirements reflect changes in engine design and exhaust systems to meet the legislated limits on emissions. The average requirement dropped approximately 5.5 Research octane numbers over the ten-year period with the most dramatic drop of approximately 3.0 octane numbers in 1971 when car manufacturers recommended use of 91 octane gasoline. The trends toward lower average requirements since 1971 have been determined with both leaded and unleaded fuels. Incidence of surface ignition knock and rumble was about one per cent in 1965 and tended to disappear after 1971. The average spread of octane number requirements between 10 and 90 per cent of cars satisfied increased about 2.5 numbers over the period.

THIS paper represents an attempt to illustrate the values of octane-number improvements in aviation gasolines in terms of increased earning power of current-type transport airplanes when proper provisions have been made in the original designs. The procedure consists in computing the change in earning power of a gallon of gasoline when octane-number changes are reflected in altered fuel consumptions or take-off load capacities.

IT is recognized that volumetric efficiency-and therefore specific output - can be increased by reduction in manifold temperature, pressure drops, and the like. The present investigation has been directed at the determination of the changes in volumetric efficiency which may be obtained by fuel-volatility variations. The results of this work may be summarized briefly as follows: (1) Very substantial improvement in engine performance can be obtained by taking advantage of suitable volatility increases. (2) A given degree of improvement in the distribution characteristics of a fuel can be attained by combining “front-end” and “total” volatilities in a fairly varied manner. (3) The distribution characteristics of a gasoline can be judged satisfactorily by using the amount evaporated at 158 deg. fahr.

THIS paper represents an attempt to appraise the general automotive-fuel situation from the viewpoint of its relation to farm-tractor fuels. In particular, the probable effects of demands for fuels other than gasoline upon costs of production and distribution have been tied-in with engine operation and maintenance costs for the purpose of indicating the most logical course for fuel and engine development. In general, the farm-tractor fuel-problem is a very important one from the viewpoint of the tractor user, due to the fact that, as farm tractors are generally used, fuel is a major cost-item amounting to more than one-third of the total cost of operation of the tractor. In spite of the fact that many other considerations logically outweigh fuel costs in importance-particularly availability of the equipment and its capacity during the seasons of peak demand-this item continues to be one which is scutinized most carefully by the user and emphasized in tractor sales.

RECENT active interest in the use of commercial butane gas as a fuel for highway-transportation equipment, particularly on the Pacific Coast, indicated to Mr. Barnard the advisability of resurveying the field of possible substitutes for gasoline, especially as regards butane. Since rapid developments in the conversion of truck fleets to use butane as fuel took place in the West, Mr. Barnard considers the possibility of the general use of butane in this class of service. After going into detail regarding the chemical properties and performances of butane and gasoline, as well as their economic aspects, Mr. Barnard concludes that an attempt to supply butane under the conditions necessary for highway units eventually would result in a final cost to the operator-on a gallonage basis-higher than that prevailing for regular gasoline. He states that no very widespread use of butane as a fuel could occur without increasing the demand to a status at which the cost would be prohibitive.