Improved Fuel Economy by Better Utilization of Available Octane Quality

The spread of octane requirements due to tolerances in engine manufacture has been investigated to indicate the potential improvement in fuel economy which could be achieved by making better use of the available gasoline octane quality.

The wide spread of octane requirements in the 48 cars studied resulted in “octane waste”, a measure of the inefficient use by engines of the available octane quality. The average waste was three octane numbers and is associated with variations in compression ratio. The wasted octane can be made available to improve fuel economy through tighter control of manufacturing tolerances on combustion chamber volumes.