Methods and Uses for Intake-Valve and Direct-Injector Deposit Clean-Up

Abstract

The use as an intake valve deposit clean-up additive in a fuel composition for a port fuel injection spark-ignition internal combustion engine or a fuel injector deposit clean-up additive in a fuel composition for a direct injection spark-ignition internal combustion engine of a combination of: a. at least one hydrocarbyl-substituted aromatic compound; and b. at least one polyalkylene amine.

What is claimed is: 
     
         1 - 11 . (canceled) 
     
     
         12 . A method of improving the port fuel injection intake valve deposit clean-up performance or the direct injection fuel injector deposit clean-up performance of a fuel composition for use in a spark-ignition internal combustion engine which method comprises incorporating into the fuel composition in one or more steps:
 a. at least one hydrocarbyl-substituted aromatic compound, such as a Mannich Base detergent; and   b. at least one polyalkylene amine, such as a polyisobutylene amine to produce a fuel composition which comprises said additives in combination and which on combustion in a spark-ignition engine produces greater port fuel injection intake valve or direct injection fuel injector deposit clean-up performance than the clean-up performance when combusting in said engine the fuel composition without said combination of additives.   
     
     
         13 . The method of  claim 12 , wherein the at least one hydrocarbyl-substituted aromatic compound is present in the fuel composition at a concentration of actives of from 20 ppm to 200 ppm. 
     
     
         14 . The method of  claim 12 , wherein the hydrocarbyl substituent of the aromatic compound exhibits a number average molecular weight of from 700 to 1500. 
     
     
         15 . The method of  claim 12 , wherein the hydrocarbyl substituent of the aromatic compound is or comprises polyisobutylene. 
     
     
         16 . The method of  claim 12 , wherein the at least one polylalkylene amine is present in the fuel composition at a concentration of actives of from 50 ppm to 500 ppm. 
     
     
         17 . The method of  claim 12 , wherein the polyalkylene amine contains a polyalkylene group that exhibits a number average molecular weight of from 700 to 1500. 
     
     
         18 . The method of  claim 12 , wherein the weight ratio of actives of polyalkylene amine:hydrocarbyl-substituted aromatic compound in the fuel composition is in the range of from 5:1 to 1:5. 
     
     
         19 . The method of  claim 12 , wherein the fuel is for a port fuel injection engine. 
     
     
         20 . A method of removing deposits from the intake valves in a port fuel injection spark-ignition internal combustion engine or the fuel injectors in a direct injection spark-ignition internal combustion engine which method comprises supplying to the engine through the port fuel injection intake valves or through the direct injection fuel injectors, a fuel composition which comprises a combination of:
 a. at least one hydrocarbyl-substituted aromatic compound, such as a Mannich Base detergent; and   b. at least one polyalkylene amine, such as a polyisobutylene amine.   
     
     
         21 . The method of  claim 20 , wherein the at least one hydrocarbyl-substituted aromatic compound is present in the fuel composition at a concentration of actives of from 20 ppm to 200 ppm. 
     
     
         22 . The method of  claim 20 , wherein the hydrocarbyl substituent of the aromatic compound exhibits a number average molecular weight of from 700 to 1500. 
     
     
         23 . The method of  claim 20 , wherein the hydrocarbyl substituent of the aromatic compound is or comprises polyisobutylene. 
     
     
         24 . The method of  claim 20 , wherein the at least one polylalkylene amine is present in the fuel composition at a concentration of actives of from 50 ppm to 500 ppm. 
     
     
         25 . The method of  claim 20 , wherein the polyalkylene amine contains a polyalkylene group that exhibits a number average molecular weight of from 700 to 1500. 
     
     
         26 . The method of  claim 20 , wherein the weight ratio of actives of polyalkylene amine:hydrocarbyl-substituted aromatic compound in the fuel composition is in the range of from 5:1 to 1:5. 
     
     
         27 . The method of  claim 20 , wherein the fuel is for a port fuel injection engine.