Two organic additives were selected for their different physico-chemical parameters to study the behaviour of a diesel-ethanol mixture. These compounds had a glycerol skeleton hearing heteroatoms and amino-ether, hydroxyl, nitrate and nitramine functional groups. Properties directly related to engine parameters (viscosity, cetane number, heat content, volatility) and those characterising fuel quality (homogeneity, cold properties, anticorrosiveness and volatility) were investigated. Fuel formulations were prepared with 2% additive and ethanol contents between 10 and 20% in volume in relation to the diesel fuel. Blends, with or without additive, are compared in two diesel engines with direct and indirect injection. Engine behaviour seemed to be improved in the presence of additives with a reduction of pollutant emissions in exhaust gas, cyclic irregularities and ignition delay. No trouble shooting, knocking or vapor-lock phenomenon were encountered during this study. (C) 2001 Elsevier Science Ltd. All rights reserved.