Fuel compositions

Abstract

Fuel composition comprising: (a) a gasoline base fuel suitable for use in a spark ignition internal combustion engine; and (b) a poly butene polymer: wherein the polybutene polymer has a molecular weight in the range from 200 to 10.000 g/mol, wherein greater than 30% of the polymer molecules in the polybutene polymer have a terminal vinylidene group and wherein the polybutene polymer is present at a level from 500 ppm to 5000 ppm, by weight of the fuel composition. The fuel compositions of the present invention provide improved engine power and reduced burn duration.

1 . Fuel composition comprising:
 (a) a gasoline base fuel suitable for use in a spark ignition internal combustion engine; and   (b) a polybutene polymer;   wherein the polybutene polymer has a number average molecular weight in the range from 200 to 10,000 g/mol, wherein greater than 30% of the polymer molecules in the polybutene polymer have a terminal vinylidene group and wherein the polybutene polymer is present at a level from 500 ppm to 5000 ppm, by weight of the fuel composition.   
     
     
         2 . Fuel composition according to  claim 1  wherein greater than 40% of the polymer molecules in the polybutene polymer have a terminal vinylidene group. 
     
     
         3 . Fuel composition according to  claim 1  wherein greater than 50% of the polymer molecules in the polybutene polymer have a terminal vinylidene group. 
     
     
         4 . Fuel composition according to  claim 1  wherein the polybutene polymer has a number average molecular weight in the range from 500 to 5,000 g/mol. 
     
     
         5 . Fuel composition according to  claim 1  wherein the polybutene polymer has a number average molecular weight in the range from 1000 to 2,300 g/mol. 
     
     
         6 . Fuel composition according to  claim 1  wherein the polybutene polymer has a number average molecular weight in the range from 2,300 to 5,000 g/mol. 
     
     
         7 . Fuel composition according to  claim 1  wherein the polybutene polymer is present at a level from 1000 ppm to 5000 ppm, by weight of the fuel composition. 
     
     
         8 . Fuel composition according to  claim 1  wherein the polybutene polymer is present at a level from 2500 ppm to 5000 ppm, by weight of the fuel composition. 
     
     
         9 . Fuel composition according to  claim 1  wherein the polybutene polymer is a polyisobutylene polymer. 
     
     
         10 . (canceled) 
     
     
         11 . (canceled) 
     
     
         12 . (canceled) 
     
     
         13 . A method of increasing the power output of a spark ignition internal combustion engine wherein the method comprises adding a polybutene to a gasoline base fuel to produce a gasoline fuel composition, wherein the polybutene polymer is added at a level from 500 ppm to 5000 ppm by weight of the gasoline fuel composition, wherein the polybutene has a number average molecular weight in the range from 200 to 10,000 g/mol and combusting the fuel composition in the spark ignition internal combustion engine. 
     
     
         14 . A method of reducing the burn duration of a gasoline fuel composition in a spark ignition internal combustion engine wherein the method comprises adding a polybutene to a gasoline base fuel to produce a gasoline fuel composition, wherein the polybutene polymer is added at a level from 500 ppm to 5000 ppm by weight of the gasoline fuel composition, wherein the polybutene has a number average molecular weight in the range from 200 to 10,000 g/mol and combusting the fuel composition in the spark ignition internal combustion engine. 
     
     
         15 . A method according to  claim 13  wherein the polybutene has greater than 30% of the polymer molecules in the polybutene polymer have a terminal vinylidene group the polybutene. 
     
     
         16 . A method according to  claim 14  wherein the polybutene has greater than 30% of the polymer molecules in the polybutene polymer have a terminal vinylidene group the polybutene.