The use of a block copolymer as detergent additive in an internal combustion engine liquid fuel, including: at least one block A of formula (I):

##STR00001##

wherein n is an integer ranging from 2 to 100, R1 is chosen from hydrogen and the methyl group, R2 is chosen from C1 to C34 hydrocarbon-based chains, at least one block B of formula (II):

##STR00002##

wherein p is an integer between 2 and 40, G is chosen from: o an aryl group, and o an aryl group substituted by at least one group chosen from: a group R, a C1 to C12 hydrocarbon-based chain, and a C1 to C12 hydrocarbon-based chain substituted by at least one group R, being chosen from the group consisting of: the groups including from 1 to 40 atoms chosen from C, N, and optionally O, including at least one primary, secondary or tertiary amine function, and quaternary ammoniums.