| abstract |
Diesel engine cylinder oils of improved cleanliness and load carrying ability and reduced port deposit characteristics for use in marine and stationary slow speed diesel engines are based on medium heavy Group I or Group II neutral base oils, typically from 300 to 500 SUS using a liquid, oil-miscible polyisobutylene (PIB) in combination with the neutral base stock and an additive package comprising a detergent component or components, an antioxidant, an antiwear agent, and a dispersant. The detergent component preferably comprises one or more overbased phenates, phenylates, salicylates or sulfonates in order to confer the desired alkalinity characteristics on the finished oil. The oils are produced in the viscosity range of 15 to 25 cS (100 °C), usually with a nominal viscosity of 20 or 24 cS, i.e., from 18.5 to 21.9 cS or 21.9 to 26.1 cS (100 °C). The viscosity index of the improved oils is at least 95, typically from 105 to 120. Total Base Number of the oils is in the range 40 to 100. |