It wants to see the higher blends to leverage the inherent high octane rating of the alcohol – and this can be used to produce ethanol-petrol blends with increased octane numbers.
At the moment, ethanol is blended into a petrol blend-stock with a lower octane rating. However, the higher octane rating could be used in a mid-level ethanol blend to increase its minimum octane number, according to the Ford researchers writing in a new paper published in the journal Fuel.
It is believed that both ethanol and methanol have performance issues in petrol blends: for example, they have a lower energy density and potentially higher or lower vapour pressures; as well as altered distillation properties. However, their high research octane number and motor octane number is an advantage: the octane number reflects its ability to resist knock, which results from premature auto-ignition.
So it is hoped that higher octane numbers can enable greater levels of thermal efficiency and more aggressive turbocharging and downsizing: helping existing engines with more aggressive spark timing in certain conditions.
For example, an increase in the blend-stock RON from 88 to 92 could offer higher RON increases in E10 from 92.5 to 95.6 with additional ethanol content.