Relating to lubricating compositions
AssigneeInfineum International Limited
InventorsGregory Stidder, Robert W. Shaw, Simon Crick
Life of this patent
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Abstract
A lubricating oil composition, a method of reducing low-speed pre-ignition (LSPI) in a direct-injected spark-ignited internal combustion engine, and a use of a lubricant composition to reduce LSPI events in such an engine. Preferably, the composition comprises a detergent comprising an overbased calcium detergent having a total base number (TBN) of at least 150, wherein the lubricating oil composition has a calcium content of at least 0.08 wt. %, based on the weight of the lubricating oil composition, and wherein the lubricating oil composition has a silicon content of at least 12 ppm by weight, based on the weight of the lubricating oil composition.
Claims45
A lubricating oil composition comprising a base oil of lubricating viscosity, one or more calcium containing detergents, and one or more silicone containing compounds, wherein:
- i) the one or more calcium containing detergents comprise a combination of a calcium salicylate detergent having a TBN of at least 64 mg KOH/g and a calcium salicylate detergent having a TBN of at least 220 mg KOH/g and the combination provides the lubricating oil composition with a calcium content of 0.184 wt. %, based on the weight of the lubricating oil composition,
- ii) the one or more silicone containing compounds provide the lubricating oil composition with a silicon content of about 20 to about 110 ppm by weight, based on the weight of the lubricating oil composition and are selected from the group consisting of polydimethylsiloxane, tetraethyl orthosilicate (Si(OEt)4), tetraethylsilane (Si(C2H5)4), tetrabutylorthosilicate (Si(OC4H9)4) and octamethylcyclotetrasilazane (C8H28N4Si4), and
- iii) when the lubricating oil composition is used to lubricate the crankcase of a direct injection-spark ignition internal combustion engine, the frequency of low-speed pre-ignition events is reduced as compared to the lubricating oil composition having less than or equal to 12 ppm by weight silicon content.
A method of reducing low-speed pre-ignition (LSPI) events in a direct-injection spark-ignition internal combustion engine comprising lubricating the crankcase of the engine with a lubricating oil composition comprising:
- a base oil of lubricating viscosity, one or more calcium containing detergents, and one or more silicone containing compounds, wherein:
- i) the one or more calcium containing detergents comprise a combination of a calcium salicylate detergent having a TBN of at least 64 mg KOH/g and a calcium salicylate detergent having a TBN of at least 220 mg KOH/g and the combination provides the lubricating oil composition with a calcium content of 0.184 wt. %, based on the weight of the lubricating oil composition,
- ii) the one or more silicone containing compounds provide the lubricating oil composition with a silicon content of about 20 to about 110 ppm by weight, based on the weight of the lubricating oil composition and are selected from the group consisting of polydimethylsiloxane, tetraethyl orthosilicate (Si(OEt)4), tetraethylsilane (Si(C2H5)4), tetrabutylorthosilicate (Si(OC4H9)4) and octamethylcyclotetrasilazane (C8H28N4Si4), and
- iii) when the lubricating oil composition is used to lubricate the crankcase of a direct injection-spark ignition internal combustion engine, the frequency of low-speed pre-ignition events is reduced as compared to the lubricating oil composition having less than or equal to 12 ppm by weight silicon content.
A lubricating oil composition comprising a base oil of lubricating viscosity, one or more calcium containing detergents, and one or more silicone containing compounds, wherein:
- i) the one or more calcium containing detergents provides the lubricating oil composition with a calcium content of 0.184 wt. %, based on the weight of the lubricating oil composition,
- ii) the one or more silicone containing compounds provide the lubricating oil composition with a silicon content of about 20 to about 110 ppm by weight, based on the weight of the lubricating oil composition and are selected from the group consisting of polydimethylsiloxane, tetraethyl orthosilicate (Si(OEt)4), tetraethylsilane (Si(C2H5)4), tetrabutylorthosilicate (Si(OC4H9)4) and octamethylcyclotetrasilazane (C8H28N4Si4), and
- iii) when the lubricating oil composition is used to lubricate the crankcase of a direct injection-spark ignition internal combustion engine, the frequency of low-speed pre-ignition events is reduced as compared to the lubricating oil composition having less than or equal to 12 ppm by weight silicon content.
Dependencies are inferred from the claim text.