Liquid fuel compositions

Abstract

A liquid fuel composition is provided containing: (a) a base fuel suitable for use in an internal combustion engine; (b) a first fuel additive selected from one or more viscosity control agents having: (i) a kinematic viscosity at 100° C. of 27 cSt or less; and (ii) a NOACK volatility at 250° C. of 100% wt or less; and (c) a second fuel additive selected from one or more friction modifiers. Fuelling such liquid fuel composition in an internal combustion engine improves the fuel economy performance of an internal combustion engine.

1 . A liquid fuel composition comprising:
 (a) a base fuel suitable for use in an internal combustion engine;   (b) a first fuel additive selected from one or more viscosity control agents having:   (i) a kinematic viscosity at 100° C. of 27 cSt or less; and   (ii) a NOACK volatility at 250° C. of 100% wt or less; and   (c) a second fuel additive selected from one or more friction modifiers.   
     
     
         2 . The liquid fuel composition of  claim 1  wherein the one or more friction modifiers is selected from the group consisting of esters or nitrogen derivatives of alkoxyamines; poly(hydroxycarboxylic) acid amide salt derivatives; poly(hydroxycarboxylic acid) derivatives having a terminal acid group; poly(hydroxycarboxylic acid) derivatives; polyetheramines; esters or nitrogen derivatives of hydroxy polycarboxylic acids; nitrogen derivatives of carboxylic acids; ester derivatives of carboxylic acids; esters of alkylsuccinic acids; alkoxylated alcohols; alkoxylated amines; alkoxylated amides or esters; and mixtures thereof. 
     
     
         3 . The liquid fuel composition of  claim 2  wherein the one or more friction modifiers is selected from the group consisting of poly(hydroxycarboxylic) acid amide salt derivatives; poly(hydroxycarboxylic acid) derivatives having a terminal acid group; poly(hydroxycarboxylic acid) derivatives; polyetheramines; ester or nitrogen derivatives of alkoxyamines; alkoxylated amides or esters; alkoxylated amines; and mixtures thereof. 
     
     
         4 . The liquid fuel composition of  claim 1  wherein the amount of the second fuel additive present in the liquid fuel composition is at least 10 ppmw, based on the overall weight of the liquid fuel composition. 
     
     
         5 . The liquid fuel composition of  claim 4  wherein the amount of the second fuel additive present in the liquid fuel composition is at most 2 wt %, based on the overall weight of the liquid fuel composition. 
     
     
         6 . The liquid fuel composition of  claim 1  wherein the first fuel additive has a NOACK volatility at 250° C. of 20% wt or less. 
     
     
         7 . The liquid fuel composition of  claim 1  wherein the first fuel additive has a NOACK volatility at 250° C. of 15% wt or less. 
     
     
         8 . The liquid fuel composition of  claim 1  wherein the first fuel additive has a NOACK volatility at 250° C. of 10% wt or less. 
     
     
         9 . The liquid fuel composition of  claim 1  wherein the first fuel additive has a NOACK volatility at 250° C. of 6% wt or less. 
     
     
         10 . The liquid fuel composition of  claim 1  wherein the first fuel additive has a kinematic viscosity at 100° C. of 17 cSt or less. 
     
     
         11 . The liquid fuel composition of  claim 1  wherein the first fuel additive has a kinematic viscosity at 100° C. in the range of from 2 cSt to 8 cSt. 
     
     
         12 . The liquid fuel composition of  claim 1  wherein the first fuel additive has a kinematic viscosity at 100° C. in the range of from 3 cSt to 8 cSt. 
     
     
         13 . The liquid fuel composition of  claim 1  wherein the first fuel additive has a kinematic viscosity at 100° C. in the range of from 4 cSt to 6 cSt. 
     
     
         14 . The liquid fuel composition of  claim 1  wherein the first fuel additive is a polyalphaolefin. 
     
     
         15 . The liquid fuel composition of  claim 9  wherein the first fuel additive is PAO-5. 
     
     
         16 . The liquid fuel composition of  claim 1  wherein the first fuel additive is an ester. 
     
     
         17 . The liquid fuel composition of  claim 16  wherein the first fuel additive is a trimethyl propane ester. 
     
     
         18 . The liquid fuel composition of  claim 1  wherein the amount of first fuel additive present in the liquid fuel composition is in the range of from 5 ppmw to 2% wt, based on weight of the liquid fuel composition. 
     
     
         19 . The liquid fuel composition of  claim 1  wherein the base fuel is a gasoline. 
     
     
         20 . A method of improving the fuel economy performance of an internal combustion engine, said method comprising (a) fuelling the internal combustion engine containing a lubricant with a liquid fuel composition of  claim 1  and (b) operating said fuelled-internal combustion engine.