Method of reducing piston deposits, smoke or wear in a diesel engine

Abstract

A method of reducing piston deposits, smoke or wear in a diesel engine. The method involves the step of running the engine on fuel comprising an oil soluble iron carboxylate or iron complex that includes Fe<SUP>3+</SUP>.

1 . A method of reducing piston deposits, smoke or wear in a diesel engine, the method involving the step of running the engine on fuel comprising an oil soluble or oil dispersible iron carboxylate or iron complex that includes Fe 3+ ; with the proviso that when the method is a method of reducing smoke in a diesel engine, the ratio of the number of equivalents of organic acid to the number of equivalents of Fe 3+  in the oil soluble or oil dispersible iron carboxylate or iron complex is 3 or more.  
     
     
         2 . The method as claimed in  claim 1 , wherein the iron carboxylate or iron complex includes more than 25% of Fe 3+ , preferably more than 50% of Fe 3+ , and most preferably more than 75% of Fe 3+ .  
     
     
         3 . The method as claimed in  claim 2 , wherein the iron carboxylate or iron complex includes more than 50% of Fe 3+ .  
     
     
         4 . The method as claimed in  claim 3 , wherein the iron carboxylate or iron complex includes more than 75% of Fe 3+ .  
     
     
         5 . The method as claimed in  claim 1 , wherein the iron carboxylate or iron complex is derived from a compound of the formula:  
       
         
           
           
               
               
           
         
       
       where R 1 , R 2 , R 3  and R 4  represent hydrogen or a hydrocarbyl having 1-30 carbon atoms (C 1 -C 30 ), but at least two of R 1 , R 2 , R 3  or R 4  are C 1 -C 30  hydrocarbyl; R 5  is a hydrocarbyl having 1 to 120 carbon atoms and m and n may each be zero or an integer such that the total number of carbon atoms in the carboxylate is not more than 125.  
     
     
         6 . The method as claimed in  claim 5 , wherein R 1  and R 2  are both hydrocarbyl and R 3  and R 4  are hydrogen.  
     
     
         7 . The method as claimed in  claim 1 , wherein the fuel is a heavy fuel oil.  
     
     
         8 . The method as claimed in  claim 1 , wherein the carboxylate is neodecanoate.  
     
     
         9 . The method as claimed in  claim 1 , wherein the fuel contains 1 to 50 ppm of iron by weight of fuel.  
     
     
         10 . The method as claimed in  claim 9 , wherein the fuel contains 1 to 25 ppm of iron by weight of fuel.  
     
     
         11 . The method as claimed in  claim 10 , wherein the fuel contains 5 to 15 ppm of iron by weight of fuel.  
     
     
         12 . The method as claimed in  claim 1 , wherein the fuel is a marine diesel fuel and the iron carboxylate is iron neodecanoate.  
     
     
         13 . The method as claimed in  claim 1 , wherein the method reduces piston groove deposits.  
     
     
         14 . The method as claimed in  claim 1 , wherein the method reduces piston deposits and smoke, or piston deposits and wear, or smoke and wear in a diesel engine.