Three European gasoline vehicles, homologated to European Stage II limits, and two US gasoline vehicles, certified to Californian TLEV limits, were evaluated over the new European test cycle for year 2000 standards and the US Federal Test Procedure.
Three advanced catalyst technologies were tested on these vehicles, in the original equipment converter position in all but one case, without any additions or changes to the existing emission control system. Prior to testing they were aged on a cycle representing 80,000 km road durability.
Up to 30% reductions in emissions were achieved from those for which the vehicles were homologated, at an incremental cost in precious metal of 12 - 23 US$ per liter of catalyst compared to the original converter precious metal value (precious metal prices of 16 July 1996).
Two of the three European vehicles achieved all the proposed new limits for Stage III using the advanced catalysts, the third European vehicle giving CO and HC emissions well within the proposed values but only achieving the NOx level with an advanced Pt/Rh formulation. In a number of instances the indicated limits for Stage IV and ULEV were met for individual pollutants. The program demonstrated that catalyst technology exists to achieve significant reductions from the Stage II limits.