US Patent 9062265 Diesel fuel compositions for high pressure fuel systems

A diesel fuel composition comprising, as an additive, a quaternary ammonium salt formed by the reaction of a compound of formula (A): and a compound formed by the reaction of a hydrocarbyl-substituted acylating agent and an amine of formula (B1) or (B2): wherein R is an optionally substituted alkyl, alkenyl, aryl or alkylaryl group; R1 is a C1 to C22 alkyl, aryl or alkylaryl group; R2 and R3 are the same or different alkyl groups having from 1 to 22 carbon atoms; X is an alkylene group having from 1 to 20 carbon atoms; n is from 0 to 20; m is from 1 to 5; and R4 is hydrogen or a C1 to C22 alkyl group.