Influence of Altitude Atmospheric Pressure on Octane Requirement (RESEARCH NOTE).

The normal specifications of motor gasolines as well as their combustion characteristics in internal combustion engines are reviewed in this paper. The effective factors influencing the fuel performance, such as the molecular structure of the fuel constituents, the operating conditions and the atmospheric pressure and temperature are also discussed. A relationship between the optimum octane number and local altitude has been formulated and plotted for a certain range of elevations. While these studies pertain only to normal compression spark-ignition engines, it is however, possible to obtain similar correlations for high compression engines by applying a different set of data