Research On Low Phosphorus Engine Oil

The research and development of high performance engine oils with a lowphosphorus has become more and more urgent due to legislation, which imposedincreasing requirement on the elimination of zinc dithiophosphates from crankcaseoils thereby improving the effectiveness of catalytic converters viable options and thedemand for increasing fuel economy. In response to the issue, a high performanceengine oil with a oil low phosphorus has been successfully formulated, its phosphoruscontent is 500ug/g.Effects of various phosphorus-free antioxidants(AO) and antiwear(AW)additives at certain concentration and the synergism and antagonism among them onthe performance of engine oil's antioxidancy, antiwear performance, detergency anddispersancy were studied thoroughly and systematically both in case of adding themalone and in combination with each other by utilizing bench tests such as PDSC,TFOUT, SRV, TEOST, Coking Panel, Soot Dispersing method. Based on these benchtests results, two kinds of formulations were developed and the optimum dosage ofthe candidate additives were determined. In addition, SEM, EPMA, AES wasperformed to identify the formation of surface-active layers on the SRV sliding steelball and their influences on performance in mixed lubrication regime, probable AWand Friction Reducing mechanisms were proposed for explaining the observed wearbehavior of organomolybdenum containing oils. Test results show that the newlydeveloped low phosphorus oils containing ADPA, BZ, OM or BZ, T533, OM haveamazingly excellent performance compared with the commercial SJ gasoline engineoil, which have passed all the severe engine tests.The results from the screening testscombined with surface analyses can provide guidance in selecting the appropriateAO/AW additives as well as formulating low phosphorus engine oils.