The Challenges of Meeting Future Emissions Legislation with a Novel Low Precious Metal TWC

This paper describes the development of a novel low precious metal nano-technology catalyst (Nanocat) and its application in a modern European gasoline vehicle.

Three iterations of low precious metal nano-technology catalysts were tested on a Euro 3 certified gasoline vehicle over the European drive cycle (EDC). Engine dynamometer lean spike ageing was used to simulate aged catalysts representing approximately 100 000 km on-road ageing. The fresh and aged nano-technology catalysts were tested and compared to the vehicle production catalyst.

The third iteration of fresh nano-technology catalyst met Euro 3 emissions legislation and also met Euro 4 limits for HC and NO_x. However, after lean spike ageing the NO_x levels exceeded Euro 3 limits but the HC tailpipe remained within Euro 4 limits. The ageing process caused an 18% reduction in the NO_x conversion but the HC conversion was maintained.

During the vehicle testing non regulated emissions were measured using online Fourier Transform Infra-Red spectroscopy (FTIR). NH₃ emissions were measured pre and post catalyst and it is postulated the production of NH₃ over the nano-technology catalyst assisted in the NO_x conversion.