Particulate emission characterization of a biodiesel vs diesel-fuelled compression ignition transport engine: A comparative study

This study was set out to characterize particulate emissions from diesel engines fuelled by (i) mineral diesel and (ii) B20 (a blend of 20% biodiesel with diesel); in terms of metals and benzene soluble organic fraction (BSOF), which is an indicator of toxicity and carcinogenicity. A medium duty, transport diesel engine (Mahindra MDI 3000) was operated at idling, 25%, 50%, 75% and rated load at maximum torque speed (1800 rpm) and samples of particulate were collected using a partial flow dilution tunnel for both fuels. Collected particulate samples were analyzed for their metal contents. In addition, metal contents in mineral diesel, biodiesel and lubricating oil were also measured to examine and correlate their (metals present in fuel) impact on particulate characteristics. Results indicated comparatively lower emission of particulate from B20-fuelled engine than diesel engine exhaust. Metals like Cd, Pb, Na, and Ni in particulate of B20 exhaust were lower than those in the exhaust of mineral diesel. However, emissions of Fe, Cr, Ni Zn, and Mg were higher in B20 exhaust. This reduction in particulate and metals in B20 exhaust was attributed to near absence of aromatic compounds, sulphur and relatively low levels of metals in biodiesel. However, benzene soluble organic fraction (BSOF) was found higher in B20 exhaust particulate compared to diesel exhaust particulate.