摘要 |
A trunk piston lubricating oil composition of TBN 20 to 60 comprising (A) a high saturates low sulphur oil of lubricating viscosity in a major amount; (B) an overbased metal hydroxybenzoate detergent additive; (C) a polyisobutene succinic anhydride additive (1-7 mass %); and (D) a meta-linear pentadecyl phenol additive (10.1 to 10 mass %), the weight ratio of (D) to (C) being less than 1 and the combined treat rate of (B), (C) and (D) being 5 to 30 %. The composition is useful to improve asphaltene dispersancy when lubricating a medium-speed compression-ignited marine engine fuelled by a heavy fuel oil. |