Marine engine lubrication

摘要

A detergent system that includes (i) an overbased C20-28 alkyl-substituted hydroxybenzoate Ca salt of TBN less than 250 and (ii) an overbased C14-18 alkylsubstituted hydroxybenzoate Ca salt of TBN less than 250, the wt % Ca ratio of (ii) to (i) being more than one, is used in a trunk piston marine lubricant to improve its asphaltene dispersancy when lubricating a medium-speed compression-ignited marine engine fuelled by a heavy fuel oil.