Claims
- 1. A method for reducing the formation of piston deposits in a diesel engine equipped with a lubricating system, which method comprises: supplying to the lubricating system of said diesel engine a diesel engine lubricating oil composition comprising a major amount of a lubricating oil, 2.5 to 7.5% by weight of a detergent, 3.5 to 6.0% by weight of a dispersant, 1.2 to 1.8% by weight of a zinc dialkyldithiophosphate and 0.2 to 2.0% by weight of a compound of formula I ##STR9## wherein X is ##STR10## and R is a straight chain or branched chain alkyl radical of the formula --C.sub.n H.sub.2n+1, wherein n is an integer from 8 to 22.
- 2. A method according to claim 1, wherein the lubricating oil is an engine oil of API classes CC, CD or class CD.sup.(+).
- 3. A method according to claim 1, wherein the lubricating oil is based on mineral oil, a synthetic oil or a mixture thereof, of SAE viscosity classes 15 W 40 or 30.
- 4. A method according to claim 1, wherein the diesel engine lubricating oil composition additionally contains 0.5 to 2.0% by weight of an antiwear agent.
- 5. A method according to claim 1, wherein the diesel engine lubricating oil composition additionally contains a triarylphosphite, a trialkylphosphite, a mixed alkylarylphosphite and/or a thio compound of formula II ##STR11## wherein R.sup.3 is C.sub.6 -C.sub.24 alkyl and m is an integer from 1 to 6.
- 6. A method according to claim 1, wherein the diesel engine lubricating oil composition contains 0.2 to 2.0% by weight of a compound of formula I, wherein n is an integer from 8 to 18.
- 7. A method according to claim 1, wherein the diesel engine lubricating oil composition contains 0.2 to 2.0% by weight of the compound octyl-3-(3,5-di-tert-butyl-4-hydroxy-phenyl)propionate.
- 8. A method according to claim 1, wherein the diesel engine lubricating oil composition contains 0.2 to 2.0% by weight of the compound n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxy-phenyl)propionate.
- 9. A method according to claim 1, wherein the diesel engine lubricating oil composition additionally contains a viscosity modifier.
- 10. A method according to claim 9, wherein the viscosity modifier is selected from the group consisting of polymethacrylates, vinylpyrrolidone/methacrylate copolymers, polybutenes, olefin copolymers and styrene/acrylate copolymers.
- 11. A method for improving the deposit control properties of a diesel engine lubricating composition containing a major amount of a lubricating oil, 2.5 to 7.5% by weight of a detergent, 3.5 to 6.0% by weight of a dispersant, and 1.2 to 1.8% by weight of a zinc dialkyldithiophosphate, which method comprises: employing in said composition 0.2 to 2.0% by weight of a compound of formula I ##STR12## wherein X is ##STR13## and R is a straight chain or branched chain alkyl radical of the formula --C.sub.n H.sub.2n+1, wherein n is an integer from 8 to 22.
- 12. A method according to claim 11, wherein the lubricating oil is an engine oil of API classes CC, CD or class CD.sup.(+).
- 13. A method according to claim 11, wherein the lubricating oil is based on mineral oil, a synthetic oil or a mixture thereof, of SAE viscosity classes 15 W 40 or 30.
- 14. A method according to claim 11, wherein the diesel engine lubricating oil composition additionally contains 0.5 to 2.0% by weight of an antiwear agent.
- 15. A method according to claim 11, wherein the diesel engine lubricating oil composition additionally contains a triarylphosphite, a trialkylphosphite, a mixed alkylarylphosphite and/or a thio compound of formula II ##STR14## wherein R.sup.3 is C.sub.6 -C.sub.24 alkyl and m is an integer from 1 to 6.
- 16. A method according to claim 11, wherein the diesel engine lubricating oil composition contains 0.2 to 2.0% by weight of a compound of formula I, wherein n is an integer from 8 to 18.
- 17. A method according to claim 11, wherein the diesel engine lubricating oil composition contains 0.2 to 2.0% by weight of the compound octyl-3-(3,5-di-tert-butyl-4-hydroxy-phenyl)propionate.
- 18. A method according to claim 11, wherein the diesel engine lubricating oil composition contains 0.2 to 2.0% by weight of the compound n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxy-phenyl)propionate.
- 19. A method according to claim 11, wherein the diesel engine lubricating oil composition additionally contains a viscosity modifier.
- 20. A method according to claim 19, wherein the viscosity modifier is selected from the group consisting of polymethacrylates, vinylpyrrolidone/methacrylate copolymers, polybutenes, olefin copolymers and styrene/acrylate copolymers.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2479/87 |
Jul 1987 |
CHX |
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Parent Case Info
This application is a continuation of Ser. No. 07/750,712, filed Aug. 20, 1991 now abandoned, which is a continuation of of application Ser. No. 07/629,098, filed Dec. 17, 1990, now abandoned, which is a continuation of application Ser. No. 07/405,373, filed Sep. 8, 1989, now abandoned, which is a continuation-in-part of application Ser. No. 07/157,825, filed Feb. 19, 1988, now abandoned.
US Referenced Citations (10)
Continuations (3)
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Number |
Date |
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Parent |
750712 |
Aug 1991 |
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Parent |
629098 |
Dec 1990 |
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Parent |
405373 |
Sep 1989 |
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Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
157825 |
Feb 1988 |
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