The Effect of Lubricant Phosphorus Level on Exhaust Emissions in a Field Trial of Gasoline Engine Vehicles 940745
The objective was to evaluate the effect of lubricant phosphorus level on catalyst converter efficiencies in a range of modern gasoline engines.
Six pairs of late model (1991 and 1992) cars were purchased for the trial. The lubricants were premium quality SW-30 oils differing only in the level of zinc dialkyldithiophosphate (ZDDP), in that one oil contained 0.12% mass phosphorus and the other oil contained 0.05% mass phosphorus. The cars were driven on local roads in a specified route of mixed conditions. The exhaust emissions were measured at 4,000, 40,000 and 80,000 km using the standard FTP 75 cycle. Oil samples were taken at 6,000 km intervals and the oil was changed at 12,000 km intervals.
At 80,000 km there was no significant lubricant effect on catalyst efficiency.
Three pairs of vehicles from this trial are continuing on to 120,000 km. In addition, the results from this field trial will be integrated with data from concurrent trials in the U.K. and Germany. Final results will be available later in 1994.