Lubricants with calcium and magnesium-containing detergents and their use for improving low-speed pre-ignition and for corrosion resistance
First Claim
1. A lubricating oil composition comprising:
- greater than 50 wt. % of a base oil of lubricating viscosity, based on a total weight of the lubricating oil composition;
one or more overbased calcium sulfonate detergents having a total base number of greater than 225 mg KOH/g, measured by the method of ASTM D-2896;
one or more overbased calcium phenate detergents having a total base number of greater than 170 mg KOH/g, measured by the method of ASTM D-2896; and
one or more overbased magnesium-containing detergents; and
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wherein a ratio of the amount of calcium in ppm by weight, based on the total weight of the lubricating oil composition to a total base number of the lubricating oil composition measured by the method of ASTM D-2896, is less than 170;
a ratio of magnesium in ppm by weight, based on a total weight of the lubricating oil composition, to total soap content in wt. %, based on a total weight of the lubricating oil composition, is greater than 700;
an amount of boron in the lubricating oil composition is up to 75 ppm by weight, based on the total weight of the lubricating oil composition; and
an amount of molybdenum in the lubricating oil composition is less than 330 ppm by weight, based on the total weight of the lubricating oil composition.
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Abstract
A lubricating oil composition and method of operating a boosted internal combustion engine with reduced low-speed pre-ignition events and corrosion resistance. The oil composition includes a base oil, one or more overbased calcium sulfonate detergents, one or more overbased calcium phenate detergents, and one or more overbased magnesium-containing detergents. A ratio of ppm of calcium to TBN of the oil composition is less than 170; a ratio of ppm of magnesium to total soap content in wt. % is greater than 700; and there are limited amounts of boron and molybdenum, and all weight percentages and ppm values being based on the total weight of the oil composition. The compositions give low LSPI ratios and pass the Ball Rust test.
135 Citations
22 Claims
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1. A lubricating oil composition comprising:
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greater than 50 wt. % of a base oil of lubricating viscosity, based on a total weight of the lubricating oil composition; one or more overbased calcium sulfonate detergents having a total base number of greater than 225 mg KOH/g, measured by the method of ASTM D-2896; one or more overbased calcium phenate detergents having a total base number of greater than 170 mg KOH/g, measured by the method of ASTM D-2896; and one or more overbased magnesium-containing detergents; and
;wherein a ratio of the amount of calcium in ppm by weight, based on the total weight of the lubricating oil composition to a total base number of the lubricating oil composition measured by the method of ASTM D-2896, is less than 170; a ratio of magnesium in ppm by weight, based on a total weight of the lubricating oil composition, to total soap content in wt. %, based on a total weight of the lubricating oil composition, is greater than 700; an amount of boron in the lubricating oil composition is up to 75 ppm by weight, based on the total weight of the lubricating oil composition; and an amount of molybdenum in the lubricating oil composition is less than 330 ppm by weight, based on the total weight of the lubricating oil composition. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for reducing a number of low-speed pre-ignition events in a boosted internal combustion engine comprising steps of:
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lubricating a boosted internal combustion engine with a lubricating oil composition comprising; greater than 50 wt. % of a base oil of lubricating viscosity, based on a total weight of the lubricating oil composition; one or more overbased calcium sulfonate detergents having a total base number of greater than 225 mg KOH/g, one or more overbased calcium phenate detergents having a total base number of greater than 170 mg KOH/g, and one or more overbased magnesium-containing detergents; and wherein a ratio of an amount of calcium in ppm to a total base number of the lubricating oil composition measured by the method of ASTM D-2896 is less than 170; a ratio of magnesium in ppm by weight, based on a total weight of the lubricating oil composition to total soap content in wt. %, based on a total weight of the lubricating oil composition is greater than 700; an amount of boron in the lubricating oil composition is up to 75 ppm by weight, based on a total weight of the lubricating oil composition; and an amount of molybdenum in the lubricating oil composition is less than 330 ppm by weight, based on a total weight of the lubricating oil composition; and operating the engine lubricated with the lubricating oil composition. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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Specification