Use of diols as detergent additives

Abstract

The present invention relates to the use, for improving the detergency properties of a liquid fuel composition comprising one or more detergent additives, of an additive consisting of one or more hydrocarbon compound(s) comprising from 2 to 10 carbon atoms and two hydroxyl functions.The present invention also relates to a method for improving the cleanliness of and/or for cleaning at least one inner portion of an internal combustion engine supplied with a liquid fuel comprising one or more detergent additives, wherein such a hydrocarbon compound is added to the fuel composition.

1 . A method for improving the detergency properties of a liquid fuel composition comprising one or more detergent additives, the method comprising:
 adding to the liquid fuel composition an additive consisting of one or more hydrocarbon compound(s) comprising from 2 to 10 carbon atoms and two hydroxyl functions.   
     
     
         2 . The method according to the preceding claim, characterised in that said hydrocarbon compound has the formula C n H 2n+2 O 2 , with n being an integer ranging from 2 to 10. 
     
     
         3 . The method according to the preceding claim, characterised in that n ranges from 3 to 8. 
     
     
         4 . The method according to the preceding claim, characterised in that said hydrocarbon compound is hexylene glycol. 
     
     
         5 . The method according to  claim 1 , characterised in that the hydrocarbon compound(s) are added to the liquid fuel composition in a total concentration ranging from 5 to 500 ppm by weight to the total weight of the fuel composition. 
     
     
         6 . The method according to  claim 1 , characterised in that the fuel composition is chosen from hydrocarbon fuels, fuels not substantially hydrocarbon fuels, and the mixtures thereof. 
     
     
         7 . The method according to  claim 1 , characterised in that the fuel composition is chosen from gasoline fuels and diesel fuels. 
     
     
         8 . The method according to  claim 1 , characterised in that the detergent additive(s) are chosen from a group consisting of amines, succinimides, alkenylsuccinimides, polyalkylamines, polyalkyl polyamines, polyetheramines, quaternary ammonium salts, derivatives of triazole, and Mannich bases. 
     
     
         9 . The method according to  claim 1 , characterised in that the total concentration of detergent additive(s) different from said hydrocarbon compounds in the fuel composition ranges from 5 to 5000 ppm by weight relative to the total weight of the fuel composition. 
     
     
         10 . The method according to  claim 1 , characterised in that the ratio between the total weight concentration of hydrocarbon compound(s) on the one hand and the total weight concentration of detergent additive(s) on the other hand ranges from 1:50 to 1:11. 
     
     
         11 . The method according to  claim 1 , to limit or avoid the formation of deposits in at least one of the inner portions of an internal combustion engine and/or to reduce the deposits existing in at least one of the inner portions of an internal combustion engine. 
     
     
         12 . The method according to the preceding claim, characterised in that the internal combustion engine is a spark-ignition engine or gasoline engine. 
     
     
         13 . The method according to  claim 11 , characterised in that the internal combustion engine is a compression-ignition engine or diesel engine. 
     
     
         14 . A method for improving the cleanliness of and/or for cleaning at least one inner portion of an internal combustion engine supplied with a liquid fuel comprising one or more detergent additives, wherein an additive consisting of at least one hydrocarbon compound as defined in  claim 1  is added to said fuel composition. 
     
     
         15 . The method according to  claim 2 , characterised in that n is 5 or 6. 
     
     
         16 . The method according to  claim 1 , further characterised in that the detergent additive(s) are Mannich bases. 
     
     
         17 . The method according to  claim 1 , further characterised in that the detergent additive(s) are quaternary ammonium salts. 
     
     
         18 . The method according to  claim 1 , further characterised in that the detergent additive(s) are polyisobutylene succinimides functionalised by a quaternary ammonium group. 
     
     
         19 . The method according to  claim 1 , characterised in that the total concentration of detergent additive(s) different from said hydrocarbon compounds in the fuel composition ranges from 20 to 250 ppm by weight relative to the total weight of the fuel composition. 
     
     
         20 . The method according to  claim 1 , characterised in that the ratio between the total weight concentration of hydrocarbon compound(s) on the one hand and the total weight concentration of detergent additive(s) on the other hand ranges from 1:20 to 1:3.