Lubricating composition and method of lubricating an internal combustion engine

Abstract

The disclosed technology relates to lubricants for compression ignition internal combustion engines, particularly those demonstrating at least one of improved seals performance, reduced deposit formation, and excellent durability. The present invention provides a low zinc lubricating composition comprising (a) an oil of lubricating viscosity, (b) a borated dispersant, and (c) a metal-free organo-phosphorus anti-wear additive, wherein the lubricating composition is substantially free of a metal containing sulfur coupled alkyl phenol compound. Further, the low zinc lubricating composition contains zinc in an amount less than 600 ppm by weight of the composition.

1 . A composition for lubricating an internal combustion engine comprising:
 an oil of lubricating viscosity; and   a DMTD derivative comprising the reaction product of 2,5-dimercapto-1,3,4-thiadiazole (“DMTD”) and an α, β-unsaturated carbonyl compound.   
     
     
         2 . The composition of  claim 1 , wherein the α, β-unsaturated carbonyl compound comprises an ester, amide, or imide. 
     
     
         3 . The composition of  claim 2 , wherein the α, β-unsaturated carbonyl compound is an ester selected from the group consisting of maleates, acrylates, methacrylates, fumarates, crotonates, itaconates, and mixtures thereof. 
     
     
         4 . The composition of  claim 3 , wherein the α, β-unsaturated ester contains 4 to 24, or 4 to 18, or 4 to 12, or 6 to 8 carbon atoms. 
     
     
         5 . The composition of  claim 3 , wherein the α, β-unsaturated ester comprises or consists of an alkyl acrylate. 
     
     
         6 . The composition of  claim 5 , wherein the alkyl acrylate comprises or consist of 2-ethyl hexyl acrylate. 
     
     
         7 . The composition of  claim 3 , wherein the α, β-unsaturated ester comprises or consist of an alkyl methacrylate. 
     
     
         8 . The composition of  claim 7 , wherein the alkyl methacrylate comprises or consists of lauryl methacrylate. 
     
     
         9 . The composition of  claim 7 , wherein the alkyl methacrylate comprises or consists of 2-ethylhexyl methacrylate. 
     
     
         10 . The composition of  claim 3 , wherein the α, β-unsaturated ester comprises or consists of a dialkyl maleate. 
     
     
         11 . The composition of  claim 10 , wherein the dialkyl maleate comprises or consists of bis-(2-ethylehexyl)maleate. 
     
     
         12 . The composition of  claim 3 , wherein the α, β-unsaturated ester comprises or consists of a dialkyl itaconate. 
     
     
         13 . The composition of  claim 12 , wherein the dialkyl itaconate comprises or consists of bis(2,4-dimethylpentyl)itaconate. 
     
     
         14 . The composition of  claim 1 , wherein the DMTD derivative is further reacted with a metal oxide, metal hydroxide, or metal alkoxide to form a metal salt. 
     
     
         15 . The composition of  claim 14 , wherein the metal is selected from zinc, titanium, molybdenum, animony, or mixtures thereof. 
     
     
         16 . The composition of  claim 1 , wherein the DMTD derivative is substantially free of or free of zinc. 
     
     
         17 . The composition of  claim 1 , wherein the DMTD derivative is further reacted with an amine to form an amine salt. 
     
     
         18 . The composition of  claim 17  wherein the amine is selected from the group consisting of methylamine, ethylamine, n-propylamine, n-butylamine, n-hexylamine, n-octylamine, 2-ethylhexylamine, benzylamine, 2-phenylethylamine, cocoamine, oleylamine, tridecylamine, isopropylamine, sec-butylamine, t-butylamine, tert-hexylamine, 1-methyl-1-amino-cyclohexane, tert-octylamine, tert-decylamine, tert-dodecylamine, tert-tetradecylamine, tert-hexadecylamine, tertoctadecylamine, tert-tetracosanylamine, and tertoctacosanylamine, cyclopentylamine, cyclohexylamine, and 1-phenylethylamine; dialkylamines, such as dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, dicyclohexylamine, di-(2-ethylhexyl)amine, dihexylamine, ethylbutylamine, N-ethylcyclohexylamine, and N-methylcyclohexylamine; cycloalkylamines, such as piperidine, N-ethylpiperidine, N,N″-dimethylpiperazine, morpholine, N-methylmorpholine, N-ethylmorpholine, N-methylpiperidine, pyrrolidine, N-methylpyrrolidine, and N-ethylpyrrolidine; and trialkylamines, such as tetramethylethylenediamine, trimethylamine, triethylamine, tripropylamine, triisopropylamine, tri-butylamine, trihexylamine, N, N-dimethylbenzylamine, dimethylethylamine, dimethylisopropylamine, dimethylbutylamine, and N, N-dimethylcyclohexylamine. 
     
     
         19 . The lubricating composition of  claim 1 , wherein the DMTD derivative is substantially free of or free of alkali metals and/or alkaline earth metals. 
     
     
         20 . The composition of  claim 1 , wherein the DMTD derivative is present in an amount to deliver at least 0.05% to 0.35% by weight or 0.07% to 0.3% by weight or 0.08% to 0.26% by weight sulfur to the lubricating composition. 
     
     
         21 . The composition of  claim 1 , wherein the lubricating composition further comprises one or more metal containing detergents. 
     
     
         22 . The composition of  claim 21 , wherein the metal of the metal containing detergent is selected from magnesium, calcium, sodium, and mixtures thereof. 
     
     
         23 . The composition of  claim 21 , wherein the detergent of the metal containing detergent is selected from sulfonates, phenates, salicylates, salixarates or mixtures thereof. 
     
     
         24 . The composition of  claim 21 , wherein the metal containing detergent comprises a calcium detergent and wherein the calcium detergent is present in an amount sufficient to deliver 500 ppm to 3000 ppm or 1000 ppm to 2500 ppm by weight calcium to the composition. 
     
     
         25 . The composition of  claim 21 , wherein the metal containing detergent comprises a magnesium detergent and wherein the magnesium detergent is present in an amount to deliver up to 500 ppm magnesium to the composition. 
     
     
         26 . The composition of  claim 1 , further comprising a molybdenum compound. 
     
     
         27 . The composition of  claim 1 , wherein the composition comprises phosphorous in amounts of 0.2 wt % or less, or 0.12 wt % or less, or 0.1 wt % or less, or 0.09 wt % or less, or 0.08 wt % or less, or 0.06 wt % or less, 0.05 wt % or less, or 0.03 wt % or less, or even 0.02 wt % or less. 
     
     
         28 . The composition of  claim 1 , wherein the composition is substantially free of or free of phosphorous. 
     
     
         29 . The composition of  claim 1 , further comprising a metal alkylthiophosphate. 
     
     
         30 . The composition of  claim 29 , wherein the metal aklylthiophosphate comprises zinc dialkyldithiophosphate. 
     
     
         31 . The composition of  claim 30 , wherein the zinc dialkyldithiophosphate is present in an amount sufficient to provide from 0.02 to 0.2 wt % zinc to the composition. 
     
     
         32 . The composition of  claim 1 , wherein the composition contains 0.015 wt % or less of zinc. 
     
     
         33 . The composition of  claim 1 , wherein the composition contains zinc in amounts of less than 0.14 wt %, or even less than 0.11 wt %, or even less than 0.09 wt %, or even less than 0.07 wt %, or even less than 0.05 wt %, or even less than 0.03 wt %, or 0.01 wt % to 0.14 wt %. 
     
     
         34 . The composition of  claim 1 , wherein the composition is substantially free of zinc. 
     
     
         35 . The composition of  claim 1 , wherein the composition contains 0.1 to 0.4 wt % sulfurized olefins. 
     
     
         36 . The composition of  claim 1 , wherein the lubricating composition is substantially free of or free of sulfurized olefin additives. 
     
     
         37 . The composition of  claim 1 , wherein the composition has a total sulfated ash content of 2 wt % or less, or 1.6 wt % or less, or 1.1 wt % or less, or 1 wt % or less, or 0.8 wt % or less, or 0.6 wt % or less, or 0.5 wt % or less, or 0.05 wt % to 0.9 wt %, or 0.1 wt % to 0.2 wt % or to 0.45. 
     
     
         38 . A method of lubricating an internal combustion engine comprising:
 operating said engine with a lubricant composition comprising as recited in  claim 1 .   
     
     
         39 . A method of decomposing peroxide in a lubricating composition used to lubricate an internal combustion engine comprising:
 supplying to said internal combustion engine the lubricating composition as recited in  claim 1 .   
     
     
         40 . (canceled)