the present invention discloses superior fuel and lubricant additives prepared by the acylation of alkyl or alkenyl succinimides with the polyether half - esters of dicarboxylic acids . the polyether half - esters of dicarboxylic acids are grafted onto the polyamine moiety of alkyl or alkenyl succinimides by reacting the succinimide and the half - ester of the dicarboxylic acid under amidation conditions to form an amide group with an amino group of the polyamine . the process is carried out by first reacting a monofunctional polyalkylene ether with a dicarboxylic acid to produce a half - ester of the dicarboxylic acid . this product is then reacted with an alkyl or alkenyl succinimide polyamine ashless dispersant to product a multifunctional hydrocarbon fuel or lubricant additive that exhibits augmented dispersant properties .