Method for controlling engine deposits in a direct injection spark ignition gasoline engine

Abstract

A method for controlling engine deposits in a direct injection spark ignition gasoline engine which comprises operating the engine with a fuel composition comprising a major amount of hydrocarbons boiling in the gasoline range and an effective deposit-controlling amount of a fuel additive composition comprising: (a) an aromatic ester compound of the formula: or a fuel soluble salt thereof, wherein R is hydroxy, nitro or —(CH2)x—NR5R6, wherein R5 and R6 are independently hydrogen or lower alkyl having 1 to 6 carbon atoms and x is 0 or 1; R1 is hydrogen, hydroxy, nitro or —NR7R8, wherein R7 and R8 are independently hydrogen or lower alkyl having 1 to 6 carbon atoms; R2 and R3 are independently hydrogen or lower alkyl having 1 to 6 carbon atoms; and R4 is a polyalkyl group having an average molecular weight in the range of about 450 to 5,000; and (b) a poly(oxyalkylene) amine having at least one basic nitrogen atom and a sufficient number of oxyalkylene units to render the poly(oxyalkylene) amine soluble in hydrocarbons boiling in the gasoline range.

Dependencies are inferred from the claim text.