Evaluation of Low Phosphorus Engine Oil Containing MoDTC

Phosphorus levels in engine oil are assumed to be lower than other oils because they cause emission catalyst poisoning. It mainly originates from zinc dithiophosphate (ZnDTP), which is an essential additive for engine oils as an antiwear agent and antioxidant. The reduction of ZnDTP in engine oils will have a great influence on this. On the other hand, fuel efficiency in vehicles is also an important issue and molybdenum dithiocarbamate (MoDTC) is very effective in improving fuel economy. Oils containing MoDTC with phosphorus content from 0.00% to 0.08% were tested using several engine and bench tests to evaluate their antiwear properties, oxidation stability and friction reduction durability. In these tests, oils containing more than 0.02% of phosphorus were able to fulfill ILSAC GF-4 performance standards with optimized additive formulation. MoDTC helped to replace several functions of ZnDTP in low phosphorus engine oils. However P0.00% oil needed more additives to improve on these functions.