Ceria-based fuel-borne catalysts have been used to promote regeneration of the DPF, by lowering the soot-combustion temperature and favoring propagation of the combustion process throughout the soot layer, and thus to ensure durability of DPF efficiency over the EURO 4 standard limits.
Since the market introduction of the PSA Peugeot Citroën DPF System for series applications, extensive works have been done to improve and simplify the DPF technology. A new enhanced ceria-based fuel-borne catalyst has been designed and developed to limit the DPF system maintenance.
This paper proposes comparative studies of two different Ceria-based fuel-borne catalysts for DPF regeneration, particularly focussing on the enhanced catalytic activity of soot combustion: correlation between soot combustion and oxygen buffering is proposed to explain difference in catalytic activity, while catalytic activity on NOx species is not affected.
The improvement of catalytic activity leads to decrease of global dosing rate in the diesel fuel that significantly reduces the ash-build up effect.
From field evaluations, characterizations of several DPFs show that ash arising from the fuel-borne catalyst strongly depends on the lubricant oil consumption, the average diesel fuel consumption and the raw engine-out PM emissions.
In relationship with those field evaluations, a second section of the paper presents mathematical models to design and optimise the DPF size in order to limit its maintenance, taking into account the global vehicle ash production.
Basically, the use of enhanced Ceria-based fuel-borne catalyst significant extends the length of the interval between DPF maintenance (ash removal by washing process) and leads to a simplification of the global DPF system offer.
That improvement places the use of Ceria-based fuel-borne catalyst to promote DPF regeneration as an attractive technical and economical approach for DPF regeneration in series passenger car applications