Diesel fuel compositions

Abstract

The use of a Fischer-Tropsch derived fuel in a fuel composition that improves the responsiveness of a compression ignition engine, such as a turbocharged direct injection diesel engine, and/or a vehicle which is powered by such engine, is provided. A method of improving the responsiveness of such an engine and/or vehicle powered by such an engine by replacing in such engine a fuel composition which contains no Fischer-Tropsch derived fuel by a Fischer-Tropsch derived fuel or a fuel composition which contains a Fischer-Tropsch derived fuel is also provided.

We claim:  
     
         1 . A method of improving the responsiveness of a compression ignition engine and/or a vehicle powered by such an engine by replacing in said engine a fuel composition which contains no Fischer-Tropsch derived fuel by a Fischer-Tropsch derived fuel or a fuel composition which contains a Fischer-Tropsch derived fuel.  
     
     
         2 . The method of  claim 1  wherein said compression ignition engine is a turbocharged direct injection diesel engine.  
     
     
         3 . The method of  claim 1  wherein the fuel composition contains 0.5 to 100% v/v of said Fischer-Tropsch derived fuel.  
     
     
         4 . The method of  claim 2  wherein the fuel composition contains 0.5 to 100% v/v of said Fischer-Tropsch derived fuel.  
     
     
         5 . The method of  claim 3  wherein the fuel composition contains 1 to 50% v/v of said Fischer-Tropsch derived fuel.  
     
     
         6 . The method of  claim 4  wherein the fuel composition contains 1 to 50% v/v of said Fischer-Tropsch derived fuel.  
     
     
         7 . The method of  claim 5  wherein the fuel composition contains 1 to 25% v/v of said Fischer-Tropsch derived fuel.  
     
     
         8 . The method of  claim 6  wherein the fuel composition contains 1 to 25% v/v of said Fischer-Tropsch derived fuel.  
     
     
         9 . A method of operating a compression ignition engine and/or a vehicle which is powered by such an engine comprising introducing into a combustion chamber of the engine a Fischer-Tropsch derived fuel or a fuel composition containing a Fischer-Tropsch derived fuel, thereby improving the responsiveness of said engine and/or said vehicle compared to a fuel composition which contains no Fischer-Tropsch derived fuel.  
     
     
         10 . The method of  claim 9  wherein said compression ignition engine is a turbocharged direct injection diesel engine.  
     
     
         11 . The method of  claim 9  wherein the fuel composition contains 0.5 to 100% v/v of said Fischer-Tropsch derived fuel.  
     
     
         12 . The method of  claim 10  wherein the fuel composition contains 0.5 to 100% v/v of said Fischer-Tropsch derived fuel.  
     
     
         13 . The method of  claim 11  wherein the fuel composition contains 1 to 50% v/v of said Fischer-Tropsch derived fuel.  
     
     
         14 . The method of  claim 12  wherein the fuel composition contains 1 to 50% v/v of said Fischer-Tropsch derived fuel.  
     
     
         15 . The method of  claim 13  wherein the fuel composition contains 1 to 25% v/v of said Fischer-Tropsch derived fuel.  
     
     
         16 . The method of  claim 14  wherein the fuel composition contains 1 to 25% v/v of said Fischer-Tropsch derived fuel.