Clean-burning aviation gasoline additive to eliminate valve seat recession and deposits

Abstract

A fuel additive for fuel formulations comprising calcium sulfonates in an amount effective to limit or eliminate valve seat recession in engines utilizing such fuel formulations. The fuel additive may also include a detergent, particularly in an amount to enhance the VSR limiting effect of the calcium sulfonates. Also included are fuel formulations containing calcium sulfonates in a concentration effective to limit vale seat recession in engines utilizing the fuel formulations. Methods for treating VSR in piston engines are also provided.

1 - 5 . (canceled) 
     
     
         6 . An aviation gasoline fuel formulation for use in an aviation engine, comprising:
 aviation gasoline comprising ETBE;   one or more calcium petroleum sulfonates in an amount of at least 5 ppm effective to limit valve seat recession in the aviation engine using the fuel; and   a detergent present in an amount to provide enhanced limiting of the VSR over that achieved with the calcium petroleum sulfonates to eliminate valve seat recession in the aviation engine using the fuel,   
       the aviation gasoline comprising a clean-burning aviation gasoline with at least a 99.6 MON octane rating comprised of at least one C 4  to C 8  aliphatic hydrocarbon and at least one oxygenated-compound and with no more than 5% m/m aromatic hydrocarbons, and no more than 1.5% m/m amines and/or no more than 0.005% m/m organometallic compounds, which formulation upon combustion prevents valve seat recession and intake coking, and reduces post-combustion deposits. 
     
     
         7 - 9 . (canceled) 
     
     
         10 . The fuel formulation of  claim 6  in which the detergent is polyolefin alkyl phenol alkyl amine to prevents intake coking and reduces post combustion deposits. 
     
     
         11 . The fuel formulation of  claim 10  which further includes the antioxidant 2,6-ditertiary butyl-4-methylphenol in an amount up to 20 mg/L. 
     
     
         12 . The fuel formulation of  claim 11  which further includes the anti-microbial agent 4,4,6-trimethyl-1,3,2-dioxaborinane in an amount up to 40 mg/L. 
     
     
         13 . The fuel formulation of  claim 12  which further includes a dye for quality control and color calibration for fuel safety. 
     
     
         14 - 20  (canceled) 
     
     
         21 . The fuel formulation of  claim 6  comprising no aromatic hydrocarbons, no amines and no organometallic compounds. 
     
     
         22 . The fuel formulation of  claim 6  comprising 5-10 ppm calcium petroleum sulfonates. 
     
     
         23 . The fuel formulation of  claim 6  comprising at least 10 ppm calcium petroleum sulfonates.