Engine lubricants for siloxane deposit control
AssigneeThe Lubrizol Corporation
InventorsVirginia A. Carrick, William D. Abraham
Life of this patent
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Abstract
A zinc free or substantially zinc free lubricant having a sulfated ash content of less than about 1.0 percent and including (a) an oil of lubricating viscosity; (b) 0.03 to about 3.0 weight percent of a phosphite compound; (c) an metal containing detergent; (d) a polyisobutylene succinimide dispersant derived from an ethylene polyamine and having a carbonyl to nitrogen ratio equal or greater than 1; (e) at least one other dispersant; (f) a boron containing compound in amount to provide at least 25 ppm boron to the lubricant composition is useful for inhibiting siloxane deposits in a stationary gas engine fueled by natural gas having a high silicon concentration.
Claims21
A method for lubricating a natural gas fueled, sump-lubricated, stationary gas engine comprising supplying to the engine a lubricant composition comprising:
- (a) an oil of lubricating viscosity;
- (b) 0.03 to about 3.0 weight percent with respect to the lubricant of a phosphite compound;
- (c) a metal containing detergent;
- (d) at least a first dispersant, wherein the first dispersant is a polyisobutylene succinimide dispersant derived from an ethylene polyamine and having a carbonyl to nitrogen ratio equal or greater than 1;
- (e) at least one other dispersant selected from the group consisting of a succinimide dispersant having a carbonyl to nitrogen ratio less than 1, a Mannich dispersant, a succinamide dispersant, and a polyisobutylene succinic acid ester dispersant;
- a boron containing compound in amount to provide at least 25 ppm boron to the lubricant composition;
- wherein the lubricant composition is free or substantially free of zinc, and
- wherein the lubricant composition has a sulfated ash content of less than about 1.0 wt. %.
20-21. (canceled)
A lubricant comprising:
- (a) an oil of lubricating viscosity;
- (b) 0.03 to about 3.0 weigh percent with respect to the lubricant composition of a phosphite compound;
- (c) a metal containing detergent;
- (d) at least a first dispersant, wherein the first dispersant is a polyisobutylene succinimide dispersant derived from an ethylene polyamine and having a carbonyl to nitrogen ratio equal or greater than 1;
- (e) at least one other dispersant selected from the group consisting of a succinimide dispersant having a carbonyl to nitrogen ratio less than 1, a Mannich dispersant, and a polyolefin succinic acid ester dispersant;
- (f) a boron containing compound in amount to provide at least 25 ppm boron to the lubricant composition;
- wherein the lubricant composition is substantially free of zinc,
- wherein the lubricant composition has a sulfated ash content of less than about 1.0 percent.
Dependencies are inferred from the claim text.