9 September 2008
Mazda announced a new diesel particulate filter (DPF) catalyst, to be launched on the new MZR-CD 2.2 diesel engine. The new catalyst promotes the oxidation of soot in the DPF by oxygen, allowing to burn off particulate matter approximately 60% faster than current systems.
Many DPF regeneration catalysts rely to a large degree on nitrogen dioxide (NO2) chemistry to oxidize soot at low temperatures. Those catalysts that also promote oxidation by oxygen, can only utilize oxygen atoms that are in close proximity to the particulate mater.
The Mazda catalyst features a proprietary activation mechanism. The ceramic catalyst carrier material has a molecular structure that enables the easy movement of oxygen stored within it. This extra oxygen can be supplied as required to increase the rate of particulate matter combustion and the DPF regeneration speed.
Combined with more precise engine control, the catalyst doubles the interval between DPF regeneration cycles, and reduces the time to complete the regeneration process to a third of the time necessary for conventional systems, said Mazda.
The new catalyst will be launched in the newly developed MZR-CD 2.2 clean diesel engine rated at 136 kW and 400 Nm torque. The fuel economy is 5.6 l/100 km. The engine will be progressively introduced to markets around the world, beginning in Europe in 2009.
Increased interest in oxygen-based DPF regeneration is driven in part by the decreasing NOx emission levels in future diesel engines, which make NO2 based regeneration problematic. DPF systems with NO2 catalysts have also been blamed for increased nitrogen dioxide concentrations measured in some European cities, that may present a public health hazard.