Particulate number legislation for gasoline direction injection vehicles tightens with Euro 6c in 2017/18.

Durability, soot regeneration, backpressure and catalyst activity are key issues, as they are for diesel particulate filters (DPF), although the challenges are very different for the different fuels, and the technologies cannot simply be transferred from one to the other.

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Three Way Filter (TWF®) technology

Johnson Matthey's Three Way Filter (TWF®) technology can reduce particle number by 50 ‐ 90% on gasoline direct injection engines.

With three way filter (TWF®) activity similar to that of flowthrough three-way catalysts (TWC), significant reductions of gaseous emissions as well as filtration of fine particles can be achieved.

Gasoline Particulate Filters (GPF) 

Gasoline Particulate Filters (GPF) systems operate at higher average temperatures than diesel particulate filters which means that passive soot regeneration occurs more readily. 

Euro 6 emission limits

Scientists at Johnson Matthey have demonstrated that it is possible to meet Euro 6 emissions limits with an aged three way filter system without the need for changes to engine hardware and calibration.

Durability trials

Durability trials have shown the TWF® system to be thermally stable as well as being resistant to poisoning.

Further development is continuing through close collaborations with vehicle and substrate manufacturers. Key challenges include durability and activity met by all parties in the real world. 

Our technical centres

Johnson Matthey's technical centres are well equipped to meet these challenges and develop TWF® technology in the required timescale.