Marine diesel engine lubricating oil composition having improved high temperature performance
AssigneeChevron Oronite Company LLC
InventorsHiroyuki Nagamatsu, Shigeru Iwamoto, Hirokazu Fujita
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Abstract
A lubricating oil composition containing a base oil of lubricating viscosity, overbased sulfurized alkylphenate detergent or its calcium salt, an overbased alkylsulfonate detergent or its calcium salt, an ashless dispersant, and a zinc dialkyldithiophosphate and/or zinc diaryidithiophosphate is described. The lubricating oil composition provides improved heat stability and anti-wear performance in marine diesel engines operated under severe conditions where the cylinder liner temperature may reach 200 to 260° C.
Claims16
A marine diesel engine lubricating oil composition having a TBN in the range of 40 to 100 and comprising:
- a) a major amount of a base oil of lubricating viscosity having a kinematic viscosity of 22 to 300 mm2/s at 40° C.,
- b) 5.0 to 35.0 wt % of an overbased sulfurized alkylphenate detergent,
- c) 2.5 to 20.0 wt % of an overbased alkylsulfonate detergent,
- d) 0.1 to 3.0 wt % of an ashless dispersant, and
- e) 0.1 to 4.0 wt % of a zinc dialkyldithiophosphate or of a zinc diaryldithiophosphate,
- wherein the weight ratio between the overbased sulfurized alkylphenate detergent and the overbased alkylsulfonate detergent is in the range of 55:45 to 95:5.
A marine diesel engine lubricating oil composition having a TBN in the range of 40 to 100 and comprising:
- a) a major amount of a base oil of lubricating viscosity having a kinematic viscosity of 22 to 300 mm2/s at 40° C.,
- b) 0.4 to 4.0 wt %, based on its calcium content, of an overbased sulfurized calcium alkylphenate detergent,
- c) 0.3 to 5.0 wt %, based on its calcium content, of an overbased calcium alkylbenzenesulfonate detergent,
- d) 0.001 to 0.1 wt %, based on its nitrogen content, of a nitrogen-containing ashless dispersant, and
- e) 0.0075 to 0.3 wt %, based on its phosphorus content, of a zinc dialkyldithiophosphate or of a zinc diaryldithiophosphate,
- wherein the weight ratio between the overbased sulfurized calcium alkylphenate detergent and the overbased calcium alkylbenzenesulfonate detergent is in the range of 55:45 to 95:5.
Dependencies are inferred from the claim text.