Patent ID: 7250065

Claim:
A method of improving the intake system cleaning effect of a fuel composition for internal combustion engines, the method consisting of: (a) providing the fuel composition with an effective amount of (i) a propoxylate additive of formula I wherein n is an integer of from 14-17, and R 1 is straight-chain or branched C 8 -C 18 -alkyl or C 8 -C 18 -alkenyl; or (b) providing the fuel composition with an effective amount of (i) a propoxylate additive of formula I and with (ii) at least one detergent additive, selected from a polyalkylamine additive of the formula II R 2 —NH 2 (II) where R 2 is a straight-chain or branched polyalkyl radical having a number average molecular weight of from about 500 to about 5000.