<div class="htmlview paragraph">The autoignition characteristics of ethanol were examined in the 667-743 K temperature range at one atmosphere. A closed static reactor testing facility, of the Le Chatelier type was employed in this study. The autoignition limits for two ethanol concentrations at varied oxygen-nitrogen concentrations are mapped out. At each fuel concentration the minimum autoignition temperature occurred at an equivalence ratio of 0.3. An Arrhenius-type expression for the ignition delay time was developed and yielded a global activation energy of 42.1 kcal/mol. Increases in ethanol and oxygen concentrations cause a decrease in ignition delay time. Ethanol concentrations proved to have a greater effect on the ignition delay times than did oxygen concentrations.</div>