Influence of Biodiesel Blending on Particulate Matter (PM) Oxidation Characteristics

The use of diesel particulate filter [DPF] has become a standard in modern diesel engine after treatment technology. However pressure drop develops across the filter as PM accumulates and this requires quick periodic burn-out without incurring thermal runaway temperatures that could compromise DPF integrity during operation. Adequate understanding of soot oxidation is needed for design and manufacture of efficient filter traps for the engine system. In this study, we have examined the impact of blending biodiesel on oxidation of PM generated from a high speed direct injection [HSDI] diesel engine, which was operated with 20% [B20] and 40% [B40] blends of two biodiesel fuels. The PM samples were collected from the engine exhaust using a Pall Tissuquartz filter, the oxidation characteristics of the samples were carried out using thermogravimetric analyzer [TGA]. The biodiesel oxidation data obtained from pure petrodiesel was compared against the fuel blends. The results show that PM obtained from fuel with biodiesel blends has less gaseous hydrocarbon emissions at the conditions collected. This showed minor effect on the start of oxidation of PM from petro diesel compared to those of blends. There is no significant effect of blending on oxidation characteristic temperatures however there is reduction in kinetic energy by 20 - 30 % during the oxidation of PM with biodiesel blend compared to PM from pure petrodiesel [B0]. The kinetics suggests that the intermolecular structures of PM with biodiesel blending have influence on oxidation characteristics.