Fuel compositions

Abstract

A diesel fuel composition comprising a performance enhancing additive, wherein the performance enhancing additive is the product of a Mannich reaction between: (a)an aldehyde; (b)a polyamine; and (c)an optionally substituted phenol; wherein the polyamine component (b) includes the moiety R 1 R 2 NCHR 3 CHR 4 NR 5 R 6 wherein each of R 1 ,R 2 R 3 ,R 4 ,R 5 and R 6 is independently selected from hydrogen, and an optionally substituted alkyl, alkenyl, alkynyl, aryl, alkylaryl or arylalkyl substituent.

1 . A diesel fuel composition comprising a performance enhancing additive, wherein the performance enhancing additive is the product of a Mannich reaction between:
 (a) an aldehyde;   (b) a polyamine; and   (c) an optionally substituted phenol;   wherein the polyamine component (b) includes the moiety R 1 R 2 NCHR 3 CHR 4 NR 5 R 6  wherein each of R 1 , R 2  R 3 , R 4 , R 5  and R 6  is independently selected from hydrogen, and an optionally substituted alkyl, alkenyl, alkynyl, aryl, alkylaryl or arylalkyl substituent;   wherein the diesel fuel composition further comprises from 0.1 to 50 ppm by weight of a metal-containing species.   
     
     
         2 . The diesel fuel composition according to  claim 1  wherein component (b) is a polyalkylene polyamine. 
     
     
         3 . The diesel fuel composition according to  claim 2  wherein component (b) is a polyethylene polyamine having between 2 and 6 nitrogen atoms. 
     
     
         4 . The diesel fuel composition according to  claim 1  wherein the additive product has a molecular weight of less than 1000. 
     
     
         5 . The diesel fuel composition according to  claim 1  wherein component (a) comprises formaldehyde. 
     
     
         6 . The diesel fuel composition according to  claim 1  wherein component (c) is an alkyl-substituted phenol which is monosubtituted at the para-position. 
     
     
         7 . The diesel fuel composition according to  claim 6  wherein the phenol is substituted with a polyisobutene residue. 
     
     
         8 . The diesel fuel composition according to  claim 6  wherein the phenol is substituted at the para position with an alkyl substituent having 10 to 15 carbon atoms. 
     
     
         9 . The diesel fuel composition according to  claim 1  wherein the performance enhancing additive is present in an amount from 0.01 to 100 ppm. 
     
     
         10 . The diesel fuel composition according to  claim 1  further comprising a nitrogen-containing detergent. 
     
     
         11 . The diesel fuel composition according to  claim 1  wherein the nitrogen-containing detergent is the product of a polyisobutene-substituted succinic acid- derived acylating agent and a polyethylene polyamine. 
     
     
         12 . The diesel fuel composition according to  claim 1  wherein the metal-containing species is present in an amount of from 0.1 to 10 ppm. 
     
     
         13 . The diesel fuel composition according to  claim 1  wherein the metal containing species is zinc. 
     
     
         14 . (canceled) 
     
     
         15 . A method for improving the engine performance of a diesel engine with a high pressure fuel system having a pressure in excess of 1350 bar comprising adding a compound to diesel fuel to form a diesel fuel composition, wherein the compound is the product of a Mannich reaction between:
 (a) an aldehyde;   (b) a polyamine; and   (c) an optionally substituted phenol, wherein the polyamine component (b) includes the moiety R 1 R 2 NCHR 3 CHR 4 NR 5 R 6  wherein each of R 1 , R 2  R 3 , R 4 , R 5  and R 6  is independently selected from hydrogen, and an optionally substituted alkyl, alkenyl, alkynyl, aryl, alkylaryl or arylalkyl substituent; wherein the diesel fuel composition further comprises from 0.1 to 50 ppm by weight of a metal-containing species.   
     
     
         16 . The method according to  claim 15  wherein the improvement in performance is measured by one or more of:
 a reduction in power loss of the engine;   a reduction in deposits on the injectors of the engine;   a reduction in deposits in the vehicle fuel filter; and   an improvement in fuel economy.