Biodiesel Influence on Particulate Matter Behavior during Active and Passive DPF Regeneration

Merging the fuel efficiency of diesel combustion with the use of renewable bio-fuels presents an attractive way towards an environmentally sustainable road transportation. But the introduction of bio-fuels have an impact on emission parameters as well as on engine and emissions after-treatment components performance and durability.

This paper relates to the evaluation of the bio-fuel influence on particulate matter characteristics produced by a diesel engine and on DPF behavior during active and passive regeneration phases. The study was based on an EN590 compatible diesel fuel commercially available (B7), an EN14214 FAME biodiesel (B100) and their blend (B20). A direct injection single cylinder diesel engine was adopted for the experimental activity. Active regeneration phase was carried out via fuel vaporizer upstream oxidation catalyst.

Results showed the particulate production rate was inversely proportional to fuel biodiesel content. Lower temperatures and temperature gradients in filtering material were measured during active regeneration events in biodiesel based experiments, while passive regeneration behavior did not show appreciable differences among the investigated blends. Additionally thermal analysis confirmed an enhanced reactivity associated with biodiesel particulate in terms of combustion rate and the formation of an higher hydrocarbon fraction. Finally a growth of ashes content in particulate matter was detected with increased biodiesel percentage.