The present invention relates to novel quaternized ammonium salts of hydrocarbyl epoxides, to the preparation thereof and to the use thereof as a fuel additive and lubricant additive, such as, more particularly, as a detergent additive; for reducing or preventing deposits in the injection systems of direct injection diesel engines, especially in common rail injection systems, for reducing the fuel consumption of direct injection diesel engines, especially of diesel engines with common rail injection systems, and for minimizing power loss in direct injection diesel engines, especially in diesel engines with common rail injection systems; and as an additive for gasoline fuels, especially for operation of DISI engines.