Lubricant Compositions For Direct Injection Engines

Abstract

The invention is directed to a method for reducing low speed pre-ignition events in a spark-ignited direct injection internal combustion engine by supplying to the sump a lubricant composition which contains an oil of lubricating viscosity and an oil soluble metal compound, wherein the metal of the oil soluble metal compound may be a group (IV) metal, which may be titanium or zirconium.

1 . A method for reducing low speed pre-ignition events in a spark-ignited direct injection internal combustion engine comprising supplying to the engine a lubricant composition comprising a base oil of lubricating viscosity and an oil soluble metal compound, wherein the metal of the metal compound is a group (IV) metal. 
     
     
         2 . The method of  claim 1 , wherein the engine is operated under a load with a brake mean effective pressure (BMEP) of greater than or equal to 10 bars. 
     
     
         3 . The method of  claim 1 , wherein the engine is operated at speeds less than or equal to 3,000 rpm. 
     
     
         4 . The method of  claim 1 , wherein the engine is fueled with a liquid hydrocarbon fuel, a liquid non-hydrocarbon fuel, or mixtures thereof. 
     
     
         5 . The method of  claim 4 , wherein the engine is fueled by natural gas, liquefied petroleum gas (LPG), compressed natural gas (CNG), or mixtures thereof. 
     
     
         6 . The method of  claim 1 , wherein the titanium compound comprises one or more of titanium (IV) oxides; titanium (IV) sulfides; titanium (IV) nitrates; titanium (IV) alkoxides; titanium phenates; titanium carboxylates, and blends thereof. 
     
     
         7 . The method of  claim 1 , wherein the titanium compound comprises a titanium alkoxide, titanium carboxylate, or blend thereof. 
     
     
         8 . The method of  claim 1  wherein the titanium compound is selected from the group consisting of titanium (IV) 2-ethyl-1-3-hexanedioate, titanium citrate, titanium oleate and blends thereof. 
     
     
         9 . The method of  claim 1  wherein the titanium compound is selected from the group consisting of titanium methoxide, titanium ethoxide, titanium propoxide, titanium isopropoxide, titanium butoxide, 2-ethylhexyl titanate and blends thereof. 
     
     
         10 . The method of  claim 1 , wherein the lubricant composition further comprises at least one other additive selected from an ashless dispersant, a metal containing overbased detergent, a phosphorus-containing antiwear additive, a friction modifier, an antioxidant, and a polymeric viscosity modifier. 
     
     
         11 . The method of  claim 1 , wherein the titanium compound is present in an amount to deliver to the lubricant composition from 10 to 1000 parts per million by weight of titanium. 
     
     
         12 . The method of  claim 1 , wherein the lubricating composition further comprises a polyalkenyl succinimide dispersant in an amount from 0.5 to 4 weight % of the composition. 
     
     
         13 . The method of  claim 1 , wherein the lubricating composition comprises at least 50 weight % of a Group II base oil, a Group III base oil, or mixtures thereof. 
     
     
         14 . The method of  claim 1 , wherein there is a reduction in the number of LSPI events of at least 10 percent. 
     
     
         15 . The method of  claim 1 , wherein the low speed pre-ignition events are reduced to less than 20 LSPI events per 100,000 combustion events. 
     
     
         16 . A method for reducing low speed pre-ignition events in a spark-ignited direct injection internal combustion engine comprising supplying to the engine a lubricant composition comprising a base oil of lubricating viscosity and 1 to 1000 parts per million by weight of titanium in the form of an oil-soluble titanium-containing material. 
     
     
         17 . The method of  claim 16 , wherein the engine is operated under a load with a brake mean effective pressure (BMEP) of greater than or equal to 10 bars. 
     
     
         18 . The method of  claim 16 , wherein the engine is operated at speeds less than or equal to 3,000 rpm. 
     
     
         19 . The method of  claim 16 , wherein the engine is fueled with a liquid hydrocarbon fuel, a liquid non-hydrocarbon fuel, or mixtures thereof. 
     
     
         20 . (canceled) 
     
     
         21 . The method of  claim 16 , wherein the titanium-containing material comprises one or more of a titanium (IV) oxide; titanium (IV) sulfide; titanium (IV) nitrate; titanium (IV) alkoxide; titanium phenate; titanium carboxylate, and blends thereof.