Some flame characteristics of motor fuels

In order to obtain some information as to the cause of the “pink” or knock of motor fuels, a photographic study has been made of the movement of flames, simultaneously with measurements of the development of pressure, during the explosion of the charge in an engine cylinder. Explosions of mixtures of pentane and air and benzene and air, at various temperatures and pressures, and of various blended mixtures of benzene and pentane, and of ethyl ether with pentane and air, have been studied. Suggestions are made for the suppression of pinking, and on the basis of these studies the differences between pinking and non-pinking explosions are pointed out.