Experimental analysis of exhaust emissions from transit buses fuelled with biodiesel.

This paper presents a real life data set that incorporates results from a Toledo Area Regional Transit Authority (TARTA) biodiesel project. The research is carried out to study the effect of biodiesel on the exhaust emissions from the public transport buses. A comprehensive exhaust emission testing protocol is developed to identify the emission variations of transit buses fuelled with blends of biodiesel under different operating modes. The study is divided into two groups: real-world on-road emission and idle-engine emission testing. Exhaust emissions of oxygen (O2), carbon monoxide (CO), sulfur dioxide (SO2), oxides of nitrogen (NOx), and carbon dioxide (CO2) have been reported in this study. The effects of biodiesel on vehicular emissions vary from pollutant to pollutant and are primarily dependent on engine characteristics and the concentration of biodiesel in the base fuel. The lower emissions are observed during the on-road test mode of CO, CO2, and SO2, with the increase in percentage of biodiesel in the base fuel. On the contrast, idle-engine emissions, except CO2, increase with the increase in percentage of biodiesel in the fuel. The emissions of NOx, SO2, and CO2 during cold-start are observed to be higher than that of the hot-start conditions.