Patent ID: 6475251
Filing Date: 2002-11-05
Classification: C10L

Abstract:
A method for reducing piston top and piston bowl deposits in a direct injection spark ignition gasoline engine which comprises operating the engine in at least stratified air/fuel charging with a fuel composition having 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 â€”(CH2)xâ€”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 â€”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.