Diesel fuel additive compositions for improvement of particulate traps

Abstract

A diesel fuel composition which improves the performance of diesel engine particulate exhaust traps comprising a diesel fuel containing a combination of 1-25 ppm of metal in the form of a metal salt additive and 100 to 500 ppm of an oil soluble nitrogen containing ashless detergent additive.

1 . A method of extending the service life of a trap for particulate exhaust emissions of a diesel engine provided with such a particulate trap, which engine, in operation, generates an exhaust stream that includes particulate emissions, said method comprising the steps of: 
 fueling the diesel engine with a fuel composition comprising diesel fuel and an additive composition comprising a combination of from 1 to 25 ppm of metal in the form of a metal salt additive and 10 to 500 ppm of a nitrogen containing oil soluble ashless detergent additive, and operating the engine.    
   
   
       2 . The method of  claim 1 , wherein the fuel composition does not contain a metal salt composed of a mixture of one or more cerium fatty acid carboxylates and 50% or more cerium oxide, unless such mixture has been added to the fuel as part of an additive combination with an ashless detergent.  
   
   
       3 . The method of  claim 1 , wherein the metal is an alkali metal, alkaline earth metal, Group IVB, VIIB, VIII, IB or IIB metal, rare earth metal, or mixtures of any of the foregoing metals.  
   
   
       4 . The method of  claim 1 , wherein the metal salt is a sulfonate, salicylate, naphthenate or neodecanoate.  
   
   
       5 . The method of  claim 1 , wherein the ashless detergent additive is a polyisobutenyl succinimide wherein the polyisobutenyl has an Mn of 400-2500.  
   
   
       6 . The method of  claim 1 , wherein there is present 10-200 ppm of the ashless detergent.  
   
   
       7 . The method of  claim 1 , wherein the metal salt is a carboxylate or complex 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.  
   
   
       8 . The method of  claim 1 , wherein the metal is calcium, iron or cerium.  
   
   
       9 . The method of  claim 2 , wherein the metal is an alkali metal, alkaline earth metal, Group IVB, VIIB, VIII, IB or IIB metal, rare earth metal, or mixtures of any of the foregoing metals.  
   
   
       10 . The method of  claim 2 , wherein the metal salt is a sulfonate, salicylate, naphthenate or neodecanoate.  
   
   
       11 . The method of  claim 2 , wherein the ashless detergent additive is a polyisobutenyl succinimide wherein the polyisobutenyl has an Mn of 400-2500.  
   
   
       12 . The method of  claim 2 , wherein there is present 10-200 ppm of the ashless detergent.  
   
   
       13 . The method of  claim 2  wherein the metal salt is a carboxylate or complex 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.  
   
   
       14 . The method of  claim 2 , wherein the metal is calcium, iron or cerium.